WikiUser_28VertebratesWCS_9606human10116ratInhibition, Cytochrome P450 enzyme (CYP17A1) activityInhibition of Cyp17A1 activityMolecular<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Cyp17a1 inhibitors bind in the active site of the enzyme by mimicking endogenous substrate, leading to a reduction in the activity of the enzyme. Cyp17A1 is the single enzyme mediating both 17 alpha-hydroxylase and 17,20-lyase activities, the distinction between the two being functional and not genetic or structural. Cyp17a1 is found in all the steroidogenic tissues such as the Leydig cells of the testes, the thecal cells of the ovaries and the adrenal cortex. Studies also detected Cyp17a1 activities in heart, adipose, liver and kidney tissue. CYP17a1 has a decisive function in steroidogenesis by constituting the initial step in a series of biochemical reactions that culminate in synthesis of steroid end-products (testosterone, estradiol, cortisol, and DHEA). Thus, any variation in Cyp17a1’s activity directly or indirectly affect steroidogenesis.<sup>12</sup></span></span></p>
<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Measurement in CYP17 MA-10 wild-type and CYP17 knock down MA-10 clone can be used to assess the effects of a dysfunction in CYP17a1 activity.<sup>3</sup></span></span></p>
<p style="text-align:justify"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>1</sup> Storbeck K., Swart P., Africander D., Conradie R., Louw R. and.Swart A.C. (2011) 16α-Hydroxyprogesterone: Origin, biosynthesis and receptor interaction. Molecular and Cellular Endocrinology, 336(1-2): 92-101<a href="https://www.google.com/url?q=https://doi.org/10.1016/j.mce.2010.11.016&sa=D&ust=1554888093195000">https://doi.org/10.1016/j.mce.2010.11.016</a></span></span></p>
<p style="text-align:justify"><span style="font-family:times new roman,times,serif"><span style="font-size:11.6667px">2</span><span style="font-size:14px"> Petrunak E.M., DeVore N.M., Patrick R. Porubsky PR.., and Scott E.E.(2014) Structures of human steroidogenic cytochrome P450 17A1 with substrates. Journal of Biological Chemistry, 289(47): 32952–32964 </span><a href="https://www.google.com/url?q=https://doi.org/10.1074/jbc.M114.610998&sa=D&ust=1554888093196000" style="font-size: 14px;">https://doi.org/10.1074/jbc.M114.610998</a><span style="font-size:14px"> </span></span></p>
<p style="text-align:justify"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>3</sup> Liu Y., Yao ZX., and Papadopoulos V. (2005) Cytochrome P450 17α Hydroxylase/17,20 Lyase (CYP17) Function in Cholesterol Biosynthesis: Identification of Squalene Monooxygenase (Epoxidase) Activity Associated with CYP17 in Leydig Cells. Molecular Endocrinology, 19(7): 1918-1931 <a href="https://www.google.com/url?q=https://doi.org/10.1210/me.2004-0271&sa=D&ust=1554888093196000">https://doi.org/10.1210/me.2004-0271</a> </span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>4</sup> Anitha B. Alex, Sumanta K. Pal, and Neeraj Agarwal (2016) CYP17 inhibitors in prostate cancer: latest evidence and clinical potential. Therapeutic Advances in Medical Oncology, 8(4):267-75 <a href="https://www.google.com/url?q=https://doi.org/10.1177/1758834016642370&sa=D&ust=1554888093193000">https://doi.org/10.1177/1758834016642370</a></span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>5</sup> Roelofs M.J., Piersma A.H., van den Berg M. and van Duursen M.B. (2013) The relevance of chemical interactions with CYP17 enzyme activity: assessment using a novel in vitro assay. Toxicology and Applied Pharmacology 1;268(3):309-17 <a href="https://www.google.com/url?q=https://doi.org/10.1016/j.taap.2013.01.033&sa=D&ust=1554888093194000">https://doi.org/10.1016/j.taap.2013.01.033</a> </span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>6</sup> Vinggaard A.M., Christiansen S., Laier P., Poulsen M.E., Breinholt V, Jarfelt K., Jacobsen H., Dalgaard M., Nellemann C. and Hass U. (2005) Perinatal exposure to the fungicide prochloraz feminizes the male rat offspring. Toxicological Sciences, 85:886–897<a href="https://www.google.com/url?q=https://doi.org/10.1093/toxsci/kfi150&sa=D&ust=1554888093194000">https://doi.org/10.1093/toxsci/kfi150</a> </span></span></p>
2019-04-10T04:54:542019-04-10T05:13:42Reduction, 17-OH-pregnenolone conversion in DHEAReduction, DHEACellular<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">17-OH-pregnenolone is the direct precursor of dehydroepiandrosterone (DHEA), a reduction in its synthesis results in a decrease in DHEA level. DHEA is defined as an obligatory intermediate in sex steroid biosynthesis being the precursor of steroid hormones like testosterone and estradiol.<sup>12</sup></span></span></p>
<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">17-OH-pregnenolone and DHEA can be fractionated using High Performance Liquid Chromatography. After separation, pregnenolone and DHEA levels can be quantify using immunoassay such as ELISA or Radio Immuno Assay (RIA). For both steroids, LC-MS/MS is also an option.</span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>1</sup> Miller Walter L. (1988) Molecular Biology of Steroid Hormone Synthesis. Endocrine Reviews, 9(3): 295-318. <a href="https://www.google.com/url?q=https://doi.org/10.1210/edrv-9-3-295&sa=D&ust=1554888093201000">https://doi.org/10.1210/edrv-9-3-295</a> </span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>2</sup> Miller W.L. and Auchus R.J. (2011) The Molecular Biology, Biochemistry, and Physiology of Human Steroidogenesis and Its Disorders. Endocrine Reviews, 32(1): 81-151.<a href="https://www.google.com/url?q=https://doi.org/10.1210/er.2010-0013&sa=D&ust=1554888093202000">https://doi.org/10.1210/er.2010-0013</a> </span></span></p>
2019-04-10T04:59:052019-04-10T05:15:50Reduction, 17-OH-progesterone conversion in androstenedioneReduction, androstenedioneCellular<p style="text-align:justify"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">17-OH-progesterone is the direct precursor of androstenedione, a reduction in its synthesis results in a decrease in androstenedione levels. Androstenedione is defined as an obligatory intermediate in sex steroid biosynthesis being the precursor of steroid hormones like testosterone and estradiol. <sup>12</sup></span></span></p>
<p style="text-align:justify"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Competitive immunoenzymatic colorimetric methods (ELISA) for quantitative determination of 17-OH-progesterone and androstenedione concentration in serum or plasma are available.</span></span></p>
<p style="text-align:justify"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Progesterone and androstenedione synthesis can be monitored using radiolabeled steroid precursor in association with High Performance Liquid Chromatography (HPLC). During synthesis, steroids will incorporate the radioactive label which can be afterwards, used for quantification. First of all, HPLC combined with internal standards can be used for steroids collection, fractionation and identification. Once separated from the other steroids, progesterone and androstenedione can be finally quantified using liquid scintillation spectrometry.</span></span></p>
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<p style="text-align:justify"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>1</sup> Miller Walter L. (1988) Molecular Biology of Steroid Hormone Synthesis. Endocrine Reviews, 9(3): 295-318. <a href="https://www.google.com/url?q=https://doi.org/10.1210/edrv-9-3-295&sa=D&ust=1554891396596000">https://doi.org/10.1210/edrv-9-3-295</a> </span></span></p>
<p style="text-align:justify"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>2</sup> Liu Y., Yao ZX., and Papadopoulos V. (2005) Cytochrome P450 17α Hydroxylase/17,20 Lyase (CYP17) Function in Cholesterol Biosynthesis: Identification of Squalene Monooxygenase (Epoxidase) Activity Associated with CYP17 in Leydig Cells. Molecular Endocrinology, 19(7): 1918-1931 <a href="https://www.google.com/url?q=https://doi.org/10.1210/me.2004-0271&sa=D&ust=1554891396596000">https://doi.org/10.1210/me.2004-0271</a> </span></span></p>
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2019-04-10T05:01:122019-04-10T05:33:19Decrease, testosterone synthesis/levelDecrease, testosterone levelCellular<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Reduction in testosterone synthesis leads to a reduction in testosterone circulating levels. <sup>12</sup></span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">ELISA kit can be used for quantitative measurement of testosterone in various samples. Liquid Chromatography- tandem Mass Spectrometry is also an option. <sup>3</sup></span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Detection of increase and decrease in the production of testosterone after chemical exposure can be measured using the validated H295R Steroidogenesis Assay associated with hormone measurement kits (ELISA) and/or instrumental techniques (LC-MS). <sup>4</sup></span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Testosterone (T) levels in a sample can be measured by (High Performance) Liquid Chromatography. After sample fractionation, testosterone can be identified by comparison with internal standards spectrum. Quantification of T levels can be performed using hormones measurements kits (ELISA), instrumental techniques (LC-MS) or liquid scintillation spectrometry (after radiolabeling).</span></span></p>
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<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px"><sup>1</sup> Miller Walter L. (1988) Molecular Biology of Steroid Hormone Synthesis. Endocrine Reviews, 9(3): 295-318. <a href="https://www.google.com/url?q=https://doi.org/10.1210/edrv-9-3-295&sa=D&ust=1554891396604000">https://doi.org/10.1210/edrv-9-3-295</a> </span></span></p>
<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px"><sup>2</sup> Elder P.A. and Lewis J.G. (1985) An enzyme-linked immunosorbent assay (ELISA) for plasma testosterone. Journal of steroid biochemistry, 22(5):635-8.</span></span></p>
<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px"><sup>3 </sup>Shiraishi S., Lee P.W., Leung A., Goh V.H., Swerdloff R.S. and Wang C. (2008) Simultaneous measurement of serum testosterone and dihydrotestosterone by liquid chromatography-tandem mass spectrometry. Clinical chemistry, 54(11): 1855-63.<a href="https://www.google.com/url?q=https://doi.org/10.1373/clinchem.2008.103846&sa=D&ust=1554891396605000">https://doi.org/10.1373/clinchem.2008.103846</a> </span></span></p>
<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px"><sup>4</sup> OECD Guideline For the Testing of Chemicals - H295R Steroidogenesis Assay (2011)<a href="https://www.google.com/url?q=https://ntp.niehs.nih.gov/iccvam/suppdocs/feddocs/oecd/oecd-tg456-2011-508.pdf&sa=D&ust=1554891396606000">https://ntp.niehs.nih.gov/iccvam/suppdocs/feddocs/oecd/oecd-tg456-2011-508.pdf</a> </span></span></p>
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2019-04-10T05:02:082019-04-10T05:20:33Decrease, dihydrotestosterone (DHT) levelDecrease, DHT levelTissue<p style="text-align:justify"><span style="font-size:11pt"><span style="background-color:white"><span style="color:black">Dihydrotestosterone (DHT) is an endogenous steroid hormone and a potent androgen. The level of DHT in tissue or blood is dependent on several factors, such as the synthesis, uptake/release, metabolism, and elimination from the system, which again can be dependent on biological compartment and developmental stage.</span></span></span></p>
<p><span style="font-size:11pt"><span style="background-color:white"><span style="color:black">DHT is primarily synthesized from testosterone (T) via the irreversible enzymatic reaction facilitated by 5α</span></span><span style="background-color:white"><span style="color:black">-Reductases (5</span></span><span style="background-color:white"><span style="color:black">α-REDs) (Swerdloff et al., 2017). Different isoforms of this enzyme are differentially expressed in specific tissues (e.g. prostate, skin, liver, and hair follicles) at different developmental stages, and depending on disease status (Azzouni et al., 2012; Uhlén et al., 2015), which ultimately affects the local production of DHT. </span></span></span></p>
<p><span style="font-size:11pt"><span style="background-color:white"><span style="color:black">An alternative (“backdoor”) pathway , exists for DHT formation that is independent of T and androstenedione as precursors. This pathway relies on the conversion of progesterone (P) or 17-OH-P to androsterone and then androstanediol through several enzymatic reactions and finally, the conversion of androstanediol into DHT probably by HSD17B6 (Miller & Auchus, 2019; Naamneh Elzenaty et al., 2022). The “backdoor” synthesis pathway is a result of an interplay between placenta, adrenal gland, and liver during fetal life (Miller & Auchus, 2019).</span></span></span></p>
<p><span style="font-size:11pt"><span style="background-color:white"><span style="color:black">The conversion of T to DHT by 5α-RED in peripheral tissue is mainly responsible for the circulating levels of DHT, though some tissues express enzymes needed for further metabolism of DHT consequently leading to little release and contribution to circulating levels (Swerdloff et al.). </span></span></span></p>
<p><span style="font-size:11pt"><span style="background-color:white"><span style="color:black">The initial conversion of DHT into inactive steroids is primarily through 3α</span></span><span style="background-color:white"><span style="color:black">-hydroxysteroid dehydrogenase (3</span></span><span style="background-color:white"><span style="color:black">α</span></span><span style="background-color:white"><span style="color:black">-HSD) and 3</span></span><span style="background-color:white"><span style="color:black">β-HSD in liver, intestine, skin, and androgen-sensitive tissues. The subsequent conjugation is mainly mediated by uridine 5´-diphospho (UDP)-glucuronyltransferase 2 (UGT2) leading to biliary and urinary elimination from the system. Conjugation also occurs locally to control levels of highly potent androgens (Swerdloff et al., 2017).</span></span></span></p>
<p><span style="font-size:11pt"><span style="background-color:white"><span style="color:black">Disruption of any of the aforementioned processes may lead to decreased DHT levels, either systemically or at tissue level.</span></span></span></p>
<p><span style="font-size:11pt"><span style="font-size:10.5pt"><span style="background-color:white"><span style="color:black">Several methods exist for DHT identification and quantification, such as conventional immunoassay methods (ELISA or RIA) and advanced analytical methods as liquid chromatography tandem mass spectrometry (LC-MS/MS). The methods can have differences in detection and quantification limits, which should be considered depending on the DHT levels in the sample of interest. Further, the origin of the sample (e.g. cell culture, tissue, or blood) will have implications for the sample preparation. </span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-size:10.5pt"><span style="background-color:white"><span style="color:black">Conventional immunoassays have limitations in that they can overestimate the levels of DHT compared to levels determined by gas chromatography mass spectrometry and liquid chromatography tandem mass spectrometry (Hsing et al., 2007; Shiraishi et al., 2008). This overestimation may be explained by lack of specificity of the DHT antibody used in the RIA and cross-reactivity with T in samples (Swerdloff et al., 2017).</span></span></span></span></p>
<p><span style="font-size:11pt">This KE is applicable to both sexes, across developmental stages and adulthood, in many different tissues and across vertebrate taxa.</span></p>
<p><span style="font-size:11pt">In both humans and rodents, DHT is important for the <em>in utero</em> differentiation and growth of the prostate and male external genitalia (Azzouni et al., 2012; Gerald & Raj, 2022). Besides its critical role in development, DHT also induces growth of facial and body hair during puberty in humans <span style="color:black">(Azzouni et al., 2012)</span>.</span></p>
<p><span style="font-size:11pt">In mammals, the role of DHT in females is less established <span style="color:black">(Swerdloff et al., 2017), however studies suggest that androgens are important in e.g. bone metabolism and growth, as well as female reproduction from follicle development to parturition (Hammes & Levin, 2019).</span></span></p>
CL:0000255eukaryotic cellHighMixedHighDuring development and at adulthoodHigh<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Azzouni, F., Godoy, A., Li, Y., & Mohler, J. (2012). The 5 alpha-reductase isozyme family: A review of basic biology and their role in human diseases. In <em>Advances in Urology</em>. https://doi.org/10.1155/2012/530121</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Gerald, T., & Raj, G. (2022). Testosterone and the Androgen Receptor. In <em>Urologic Clinics of North America</em> (Vol. 49, Issue 4, pp. 603–614). W.B. Saunders. https://doi.org/10.1016/j.ucl.2022.07.004</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Hammes, S. R., & Levin, E. R. (2019). Impact of estrogens in males and androgens in females. In <em>Journal of Clinical Investigation</em> (Vol. 129, Issue 5, pp. 1818–1826). American Society for Clinical Investigation. https://doi.org/10.1172/JCI125755</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Hsing, A. W., Stanczyk, F. Z., Bélanger, A., Schroeder, P., Chang, L., Falk, R. T., & Fears, T. R. (2007). Reproducibility of serum sex steroid assays in men by RIA and mass spectrometry. <em>Cancer Epidemiology Biomarkers and Prevention</em>, <em>16</em>(5), 1004–1008. https://doi.org/10.1158/1055-9965.EPI-06-0792</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Miller, W. L., & Auchus, R. J. (2019). The “backdoor pathway” of androgen synthesis in human male sexual development. <em>PLoS Biology</em>, <em>17</em>(4). https://doi.org/10.1371/journal.pbio.3000198</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Naamneh Elzenaty, R., du Toit, T., & Flück, C. E. (2022). Basics of androgen synthesis and action. In <em>Best Practice and Research: Clinical Endocrinology and Metabolism</em> (Vol. 36, Issue 4). Bailliere Tindall Ltd. https://doi.org/10.1016/j.beem.2022.101665</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Shiraishi, S., Lee, P. W. N., Leung, A., Goh, V. H. H., Swerdloff, R. S., & Wang, C. (2008). Simultaneous measurement of serum testosterone and dihydrotestosterone by liquid chromatography-tandem mass spectrometry. <em>Clinical Chemistry</em>, <em>54</em>(11), 1855–1863. https://doi.org/10.1373/clinchem.2008.103846</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Swerdloff, R. S., Dudley, R. E., Page, S. T., Wang, C., & Salameh, W. A. (2017). Dihydrotestosterone: Biochemistry, physiology, and clinical implications of elevated blood levels. In <em>Endocrine Reviews</em> (Vol. 38, Issue 3, pp. 220–254). Endocrine Society. https://doi.org/10.1210/er.2016-1067</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Uhlén, M., Fagerberg, L., Hallström, B. M., Lindskog, C., Oksvold, P., Mardinoglu, A., Sivertsson, Å., Kampf, C., Sjöstedt, E., Asplund, A., Olsson, I. M., Edlund, K., Lundberg, E., Navani, S., Szigyarto, C. A. K., Odeberg, J., Djureinovic, D., Takanen, J. O., Hober, S., … Pontén, F. (2015). Tissue-based map of the human proteome. <em>Science</em>, <em>347</em>(6220). https://doi.org/10.1126/science.1260419</span></span></p>
2019-04-10T05:02:292023-10-19T07:13:56Decrease, androgen receptor activationDecrease, AR activationTissue<p><span style="font-size:11pt">This KE refers to decreased activation of the androgen receptor (AR) as occurring in complex biological systems such as tissues and organs in vivo. It is thus considered distinct from KEs describing either blocking of AR or decreased androgen synthesis.</span></p>
<p style="text-align:justify"><span style="font-size:11pt">The AR is a nuclear transcription factor with canonical AR activation regulated by the binding of the androgens such as testosterone or dihydrotestosterone (DHT). Thus, AR activity can be decreased by reduced levels of steroidal ligands (testosterone, DHT) or the presence of compounds interfering with ligand binding to the receptor <span style="color:black">(Davey & Grossmann, 2016; Gao et al., 2005)</span>.</span></p>
<p style="text-align:justify"><span style="font-size:11pt">In the inactive state, AR is sequestered in the cytoplasm of cells by molecular chaperones. In the classical (genomic) AR signaling pathway, AR activation causes dissociation of the chaperones, AR dimerization and translocation to the nucleus to modulate gene expression. AR binds to the androgen response element <span style="color:black">(Davey & Grossmann, 2016; Gao et al., 2005)</span>. AR does not, however, act alone in regulating gene transcription, but together with other co-factors that may differ between cells and tissues and life stages. In this way, the functional consequence of AR activation is cell- and tissue-dependent. </span></p>
<p style="text-align:justify"><span style="font-size:11pt">Ligand-bound AR may also associate with cytoplasmic and membrane-bound proteins to initiate cytoplasmic signaling pathways with other functions than the nuclear pathway. Non-genomic AR signaling includes association with Src kinase to activate MAPK/ERK signaling and activation of the PI3K/Akt pathway. Decreased AR activity may therefore be a decrease in the genomic and/or non-genomic AR signaling pathways <span style="color:black">(Leung & Sadar, 2017)</span>.</span></p>
<p><span style="font-size:11pt">This KE specifically focuses on decreased <em>in vivo</em> activation, with most methods that can be used to measure AR activity carried out <em>in vitro</em>. They provide indirect information about the KE and are described in lower tier MIE/KEs (see MIE/KE-26 for AR antagonism, KE-1690 for decreased T levels and KE-1613 for decreased dihydrotestosterone levels). In this way, this KE is a placeholder for tissue-specific responses to AR activation or inactivation that will depend on the adverse outcome (AO) for which it is included. </span></p>
<p style="text-align:justify"><span style="font-size:11pt">It should be mentioned that the Rapid Androgen Disruption Activity Reporter (RADAR) assay included in OECD test guideline no. 251 detects AR antagonism in vivo in fish (OECD 2022).</span></p>
<p><span style="font-size:11pt">This KE is considered broadly applicable across vertebrate taxa as all vertebrate animals express the AR in numerous cells and tissues where it regulates gene transcription required for developmental processes and functions. </span></p>
HighMixedHighDuring development and at adulthoodHigh<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Davey, R. A., & Grossmann, M. (2016). Androgen Receptor Structure, Function and Biology: From Bench to Bedside. <em>The Clinical Biochemist. Reviews</em>, <em>37</em>(1), 3–15.</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Gao, W., Bohl, C. E., & Dalton, J. T. (2005). Chemistry and structural biology of androgen receptor. <em>Chemical Reviews</em>, <em>105</em>(9), 3352–3370. https://doi.org/10.1021/cr020456u</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Hutson, J. M. (1985). A biphasic model for the hormonal control of testicular descent. <em>The Lancet</em>, <em>24</em>, 419–421. https://doi.org/https://doi.org/10.1016/S0140-6736(85)92739-4</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Kaftanovskaya, E. M., Huang, Z., Barbara, A. M., de Gendt, K., Verhoeven, G., Gorlov, I. P., & Agoulnik, A. I. (2012). Cryptorchidism in mice with an androgen receptor ablation in gubernaculum testis. <em>Molecular Endocrinology</em>, <em>26</em>(4), 598–607. https://doi.org/10.1210/me.2011-1283</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Lee, S. H., Hong, K. Y., Seo, H., Lee, H. S., & Park, Y. (2021). Mechanistic insight into human androgen receptor-mediated endocrine-disrupting potentials by a stable bioluminescence resonance energy transfer-based dimerization assay. <em>Chemico-Biological Interactions</em>, <em>349</em>. https://doi.org/10.1016/j.cbi.2021.109655</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Leung, J. K., & Sadar, M. D. (2017). Non-Genomic Actions of the Androgen Receptor in Prostate Cancer. <em>Frontiers in Endocrinology</em>, <em>8</em>. <a href="https://doi.org/10.3389/fendo.2017.00002" style="color:#0563c1; text-decoration:underline">https://doi.org/10.3389/fendo.2017.00002</a></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">OECD (2022). Test No. 251: Rapid Androgen Disruption Activity Reporter (RADAR) assay. Paris: OECD Publishing doi:10.1787/da264d82-en.</span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Pang, T. P. S., Clarke, M. v., Ghasem-Zadeh, A., Lee, N. K. L., Davey, R. A., & MacLean, H. E. (2012). A physiological role for androgen actions in the absence of androgen receptor DNA binding activity. <em>Molecular and Cellular Endocrinology</em>, <em>348</em>(1), 189–197. https://doi.org/10.1016/j.mce.2011.08.017</span></span></p>
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2019-04-10T05:04:182023-10-19T07:21:18Impaired inguinoscrotal testicular descent phaseImpaired inguinoscrotal phaseOrgan<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Testis descent is based on a two-phase process: the transabdominal phase (INSL3-mediated) and the inguinoscrotal phase (Androgen-dependent). The transabdominal phase takes place in the first months of pregnancy, between 10 and 15 weeks. The inguinoscrotal phase occurs later in the fetus development, about 25-35 weeks of gestation. During this second phase, the testis is supposed to get into the scrotum. A defect in the inguinoscrotal phase results in a dysfunction in testis migration: the testis is stuck in the abdominal part of the body.<sup>1</sup></span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Any impairment in testis migration, either through the transabdominal phase or the inguinoscrotal phase, will directly result in the absence of one or both testes from the scrotum.</span></span></p>
<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px"><sup>1</sup> Hutson J.M., Li R., Southwell B.R., Newgreen D., and Cousinery M. (2015) Regulation of testicular descent. Pediatric Surgery International, 31(4): 317-325 <a href="https://www.google.com/url?q=https://doi.org/10.1007/s00383-015-3673-4&sa=D&ust=1554891396640000">https://doi.org/10.1007/s00383-015-3673-4</a> </span></span></p>
2019-04-10T05:05:262019-04-10T05:25:15Malformation, cryptorchidism - maldescended testisMalformation, cryptorchidismOrgan<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Undescended testis is a testicular disorder syndrome known as cryptorchidism. Testis migration is a major event in male fetus development, as it will directly affect his reproductive health.</span></span></p>
<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Cryptorchidism can defined itself as the insertion of the testis in another position than the scrotum. Although the events leading to this pathology occurred during development, cryptorchidism can only be defined after birth though clinical examination as palpation.</span></span></p>
<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Cryptorchidism can be either uni- or bilateral and has been reported to increase in incidence over the decades (Denmark, UK, India…). The maldescended testis will experiment heat stress (37 against 33C outside the body) interfering with testicular physiology and development of germ cells into spermatogonia. Germ cells maturation failure will induce a non-reversible reduction in fertility power of the individual. Cryptorchidism is an established risk factor for infertility and is known to increase the incidence of testicular germ cell tumors (TGCT) <sup>123</sup></span></span></p>
<p style="text-align: justify;"> </p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Remark: </span></span></p>
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<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Cryptorchidism is the first AO of a larger list including raise in testicular cancer and germ cell tumor incidence, as well as reduced fertility due to impairment in germ cells maturation.</span></span></p>
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<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Cryptorchidism is a birth defect that can be highlighted by a clinical examination. The aim of this palpation is to locate the gonad and determine its lowest position without causing painful traction on the spermatic cord. <sup>4</sup></span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>1</sup> Hutson J.M., Li R., Southwell B.R., Newgreen D., and Cousinery M. (2015) Regulation of testicular descent. Pediatric Surgery International, 31(4): 317-325. <a href="https://www.google.com/url?q=https://doi.org/10.1007/s00383-015-3673-4&sa=D&ust=1554891396648000">https://doi.org/10.1007/s00383-015-3673-4</a> </span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>2</sup> Boisen K.A., Kaleva M., Main K.M., Virtanen H.E., Haavisto A.M., Schmidt I.M., Chellakooty M., Damgaard I.N., Mau C., Reunanen M., Skakkebaek N.E. and Toppari J. (2004) Difference in prevalence of congenital cryptorchidism in infants between two Nordic countries. Lancet, 17;363(9417):1264-9 <a href="https://www.google.com/url?q=https://doi.org/10.1016/S0140-6736(04)15998-9&sa=D&ust=1554891396649000">https://doi.org/10.1016/S0140-6736(04)15998-9</a> </span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>3</sup> Acerini C.L., Miles H.L., Dunger D.B., Ong K.K. and Hughes I.A. (2009) The descriptive epidemiology of congenital and acquired cryptorchidism in a UK infant cohort. Archives of disease in childhood, 94(11):868-72 https://doi.org10.1136/adc.2008.150219 </span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>4</sup> Hutson J.M., et al. (2015) Cryptorchidism and Hypospadias. Endotext<a href="https://www.google.com/url?q=https://www.ncbi.nlm.nih.gov/books/NBK279106/&sa=D&ust=1554891396651000">https://www.ncbi.nlm.nih.gov/books/NBK279106/</a> </span></span></p>
2019-04-10T05:06:572019-04-10T05:27:42c9feebaa-09be-44eb-aa74-145442c481cfb8b0f47d-0c38-42f8-b99d-97c3a56bef80<table>
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<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Cyp17a1 catalyzes the conversion of 17-OH-pregnenolone in DHEA through its 17α-hydroxylase activity. DHEA is synthesized by the cleavage of the c17,20 bond of 17-OH-pregnenolone. A lack in Cyp17a1’s activity directly affect this process resulting in a reduction in DHEA levels Cyp17a1 is found mainly found in Leydig cells and in the zona fasciculata/zona reticularis of the adrenal cortex. <sup>123</sup></span></span></p>
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<p style="text-align: justify;">The biological role of Cyp17a1 in 17-OH-pregnenolone/DHEA conversion is very well established. Cyp17a1 is known to cleave the c17,20bond of 10-OH-pregnenolone through its 17α-hydroxylase activity.<sup> 123</sup></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">A major empirical evidence came from CYP17 knock down cell studies. In 2005, Liu Y., Yao ZX., and Papadopoulos V. showed that MA-10 CYP17 knock down cells synthesize much less pregnenolone and DHEA compared with MA-10 wild type cells. In this study, de novo endogenous cholesterol synthesis was blocked with the 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor lovastatin. After cells incubation with a radiolabeled cholesterol precursor ([3H]mevalonactone), progesterone and DHEA were fractionned using HPLC and identify using standards. After quantification by liquid scintillation spectrometry, results indicated that the MA-10CYP17KD cells synthesize much less pregnenolone, progesterone and DHEA. These results enable to highlight the important factor of CYP17a1 in 17-OH-pregnenolone conversion to DHEA. <sup>4</sup></span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">The mentioned study is based on MA-10 mouse tumor Leydig cells. Even though mouse is the prefered animal model for reproductive studies, a human-cell based study would be stronger.</span></span></p>
<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px"><sup>1</sup> Miller Walter L. (1988) Molecular Biology of Steroid Hormone Synthesis. Endocrine Reviews, 9(3): 295-318. <a href="https://www.google.com/url?q=https://doi.org/10.1210/edrv-9-3-295&sa=D&ust=1554891396513000">https://doi.org/10.1210/edrv-9-3-295</a> </span></span></p>
<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px"><sup>2</sup> Miller W.L. and Auchus R.J. (2011) The Molecular Biology, Biochemistry, and Physiology of Human Steroidogenesis and Its Disorders. Endocrine Reviews, 32(1): 81-151.<a href="https://www.google.com/url?q=https://doi.org/10.1210/er.2010-0013&sa=D&ust=1554891396514000">https://doi.org/10.1210/er.2010-0013</a> </span></span></p>
<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px"><sup>3</sup> Auchus R.J. (2004) Overview of dehydroepiandrosterone biosynthesis. Seminars in Reproductive Medicine, 22(4):281-8.<a href="https://www.google.com/url?q=https://doi.org/10.1055/s-2004-861545&sa=D&ust=1554891396515000">https://doi.org/10.1055/s-2004-861545</a> </span></span></p>
<p style="text-align: justify;"><span style="font-family:times new roman,times,serif"><span style="font-size:14px"><sup>4 </sup>Liu Y., Yao ZX., and Papadopoulos V. (2005) Cytochrome P450 17α Hydroxylase/17,20 Lyase (CYP17) Function in Cholesterol Biosynthesis: Identification of Squalene Monooxygenase (Epoxidase) Activity Associated with CYP17 in Leydig Cells. Molecular Endocrinology, 19(7): 1918-1931 <a href="https://www.google.com/url?q=https://doi.org/10.1210/me.2004-0271&sa=D&ust=1554891396516000">https://doi.org/10.1210/me.2004-0271</a> </span></span></p>
2019-04-10T05:28:442019-04-10T05:31:29c9feebaa-09be-44eb-aa74-145442c481cf76ea0161-bc87-45c8-a98c-5289ea1dae17<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Cyp17a1 catalyzes the cleavage of c17,20 bond of 17-OH-progesterone to give androstenedione. This pathway is a direct conversion of DHEA by the enzyme 3β-hydroxysteroid dehydrogenase. A diminution in Cyp17a1 activity leads to a reduction in both 17-OH-progesterone/androstenedione and DHEA/androstenedione conversion. <sup>123</sup></span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">The biological role of Cyp17a1 in 17-OH-progesterone/androstenedione conversion is very well known. Most of androstenedione is synthesized through the 17,20-lyase activity of Cyp17a1. <sup>123</sup></span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Using MA-10 CYP17 knock down cells, Liu Y., Yao ZX., and Papadopoulos V. showed that cells without CYP17 enzyme tend to synthesize less progesterone than MA-10 wild type cells. For this particular study, endogenous cholesterol synthesis was blocked using 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor lovastatin. Cells were incubated with a radioactive cholesterol precursor to allow steroidogenesis monitoring. Newly-synthesized steroids were then collected, separated and identified using HPLC. After quantification by liquid scintillation spectrometry, results indicated that the MA-10CYP17KD cells synthesize much less progesterone than wild type cells. These results enable to highlight the important factor of CYP17a1 in 17-OH-progesterone conversion in androstenedione <sup>4</sup></span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">The mentioned study is based on MA-10 mouse tumor Leydig cells. Even though mouse is the prefered animal model for reproductive studies, a human-cell based study would be stronger.</span></span></p>
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<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>1</sup> Miller Walter L. (1988) Molecular Biology of Steroid Hormone Synthesis. Endocrine Reviews, 9(3): 295-318. <a href="https://www.google.com/url?q=https://doi.org/10.1210/edrv-9-3-295&sa=D&ust=1554891396526000">https://doi.org/10.1210/edrv-9-3-295</a> </span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>2</sup> Miller W.L. and Auchus R.J. (2011) The Molecular Biology, Biochemistry, and Physiology of Human Steroidogenesis and Its Disorders. Endocrine Reviews, 32(1): 81-151.<a href="https://www.google.com/url?q=https://doi.org/10.1210/er.2010-0013&sa=D&ust=1554891396526000">https://doi.org/10.1210/er.2010-0013</a> </span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><sup>3</sup> Liu Y., Yao ZX., and Papadopoulos V. (2005) Cytochrome P450 17α Hydroxylase/17,20 Lyase (CYP17) Function in Cholesterol Biosynthesis: Identification of Squalene Monooxygenase (Epoxidase) Activity Associated with CYP17 in Leydig Cells. Molecular Endocrinology, 19(7): 1918-1931 <a href="https://www.google.com/url?q=https://doi.org/10.1210/me.2004-0271&sa=D&ust=1554891396527000">https://doi.org/10.1210/me.2004-0271</a> </span></span></p>
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2019-04-10T05:32:542019-04-10T05:35:35b8b0f47d-0c38-42f8-b99d-97c3a56bef801a167e3b-27fc-48a0-9db2-4b530efb144e2019-06-03T08:39:292019-06-03T08:39:2976ea0161-bc87-45c8-a98c-5289ea1dae171a167e3b-27fc-48a0-9db2-4b530efb144e2019-06-03T08:40:002019-06-03T08:40:001a167e3b-27fc-48a0-9db2-4b530efb144e3274122b-a87b-4113-a186-cbf844b9e4942019-06-03T08:40:162019-06-03T08:40:163274122b-a87b-4113-a186-cbf844b9e494ef275245-bd24-4c5a-b011-9c46b6f6bdad<p><span style="font-size:11.0pt">Dihydrotestosterone (DHT) is a primary ligand for the Androgen receptor (AR), a nuclear receptor and transcription factor. DHT is an endogenous sex hormone that is synthesized from e.g. testosterone by the enzyme 5α-reductase in different tissues and organs </span><span style="font-size:11.0pt">(<a href="#_ENREF_1" title="Davey, 2016 #250">Davey & Grossmann, 2016</a>; <a href="#_ENREF_3" title="Marks, 2004 #283">Marks, 2004</a>)</span><span style="font-size:11.0pt">. In the absence of ligand (e.g. DHT) the AR is localized in the cytoplasm in complex with molecular chaperones. Upon ligand binding, AR is activated, translocated into the nucleus, and dimerizes to carry out its ‘genomic function’ </span><span style="font-size:11.0pt">(<a href="#_ENREF_1" title="Davey, 2016 #250">Davey & Grossmann, 2016</a>)</span><span style="font-size:11.0pt">. Hence, AR transcriptional function is directly dependent on the presence of ligands, with DHT being a more potent AR activator than testosterone (<a href="#_ENREF_2" title="Grino, 1990 #284">Grino et al, 1990</a>). Reduced levels of DHT may thus lead to reduced AR activation. Besides its genomic actions, the AR can also mediate rapid, non-genomic second messenger signaling (Davey and Grossmann, 2016). Decreased DHT levels that lead to reduced AR activation can thus entail downstream effects on both genomic and non-genomic signaling. </span></p>
<p><span style="font-size:11pt">The biological plausibility of KER1935 is considered high.</span></p>
<p><span style="font-size:11pt">The activation of AR is dependent on binding of ligands (though a few cases of ligand-independent AR activation has been shown, see <em>uncertainties and inconsistencies</em>), primarily testosterone and DHT in most vertebrates and 11-ketotestosterone in teleost fishes (Schuppe et al., 2020). Without ligand activation, the AR will remain in the cytoplasm associated with heat-shock and other chaperones and not be able to carry out its canonical (‘genomic’) function. Upon androgen binding, the AR undergoes a conformational change, chaperones dissociate, and a nuclear localization signal is exposed. The androgen/AR complex can now translocate to the nucleus, dimerize and bind AR response elements to regulate target gene expression (Davey and Grossmann, 2016; Eder et al., 2001).</span></p>
<p><span style="font-size:11pt">The requirement for androgens binding to the AR for transcriptional activity has been extensively studied and proven and is generally considered textbook knowledge. The OECD test guideline no. 458 uses DHT as the reference chemical for testing androgen receptor activation <em>in vitro</em> (OECD, 2020). In the absence of DHT during development caused by 5α-reductase deficiency (i.e. still in the presence of testosterone) male fetuses fail to masculinize properly. This is evidenced by, for instance, individuals with congenital 5α-reductase deficiency conditions (Costa et al., 2012); conditions not limited to humans (Robitaille and Langlois, 2020), testifying to the importance of specifically DHT for AR activation and subsequent masculinization of certain reproductive tissues. </span></p>
<p><span style="font-size:11pt">Binding of testosterone or DHT has differential effects in different tissues. E.g. in the developing mammalian male; testosterone is required for development of the internal sex organs (epididymis, vas deferens and the seminal vesicles), whereas DHT is crucial for development of the external sex organs (Keller et al., 1996; Robitaille and Langlois, 2020). </span></p>
<p><span style="font-size:11pt">The empirical support for KER1935 is considered high.</span></p>
<p><span style="font-size:11pt">Dose concordance:</span></p>
<ul>
<li><span style="font-size:11pt">Increasing concentrations of DHT lead to increasing AR activation <em>in vitro</em> in AR reporter gene assays (OECD, 2020; Williams et al., 2017).</span></li>
<li><span style="font-size:11pt">In cell lines where proliferation can be induced by androgens (such as prostate cancer cells) proliferation can be used as a readout for AR-activation. Finasteride, a 5α-reductase inhibitor, dose-dependently decreases AR-mediated prostate cancer cell line proliferation (Bologna et al., 1995). 0.001 µM finasteride decreased the growth rate with 44%, 0.1 µM decreased the growth rate with 80%. </span></li>
<li><span style="font-size:11pt">Specific events of masculinization during development are dependent on AR activation by DHT, including the development and length of the perineum which can be measured as the anogenital distance (AGD, (Schwartz et al., 2019)). E.g. a dose-dependent effect of rat <em>in utero</em> exposure to the 5α-reductase inhibitor finasteride was observed on the length of the AGD, where 0.01 mg/kg bw/day finasteride reduced the AGD measured at pup day 1 by 8%, whereas 1 mg/kg bw/day reduced the AGD by 23% (Bowman et al., 2003).</span></li>
</ul>
<p><span style="font-size:11pt">Other evidence:</span></p>
<ul>
<li><span style="font-size:11pt">Male individuals with congenital 5α-reductase deficiency (absence of DHT) fail to masculinize properly (Costa et al., 2012). </span></li>
<li><span style="font-size:11pt">A major driver of prostate cancer growth is AR activation (Davey and Grossmann, 2016; Huggins and Hodges, 1941). Androgen deprivation is used as treatment including 5α-reductase inhibitors to reduce DHT levels (Aggarwal et al., 2010).</span></li>
</ul>
<p><span style="font-size:11pt">Ligand-independent actions of the AR have been identified. To what extent and of which biological consequences is not well defined (Bennesch and Picard, 2015). </span></p>
<p><span style="font-size:11pt">It should be noted, that in tissues, that are not DHT-dependent but rather respond to T, a decrease in DHT level may not influence AR activation significantly in that specific tissue. </span></p>
HighMixedHighDuring development and at adulthoodHigh<p><span style="font-size:11pt"><strong>Taxonomic applicability</strong></span></p>
<p><span style="font-size:11pt">KER1935 is assessed applicable to vertebrates, as DHT and AR activation are known to be related in these species.</span></p>
<p><span style="font-size:11pt"><strong>Sex applicability</strong></span></p>
<p><span style="font-size:11pt">KER1935 is assessed applicable to both sexes, as DHT activates AR in both males and females.</span></p>
<p><span style="font-size:11pt"><strong>Life-stage applicability</strong></span></p>
<p><span style="font-size:11pt">KER1935 is considered applicable to developmental and adult life stages, as DHT-mediated AR activation is relevant from the AR is expressed.</span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Aggarwal, S., Thareja, S., Verma, A., Bhardwaj, T.R., Kumar, M., 2010. An overview on 5α-reductase inhibitors. Steroids 75, 109–153. https://doi.org/10.1016/j.steroids.2009.10.005</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Bennesch, M.A., Picard, D., 2015. Minireview: Tipping the Balance: Ligand-Independent Activation of Steroid Receptors. Mol. Endocrinol. 29, 349–363. https://doi.org/10.1210/ME.2014-1315</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Bhasin, S., Cunningham, G.R., Hayes, F.J., Matsumoto, A.M., Snyder, P.J., Swerdloff, R.S., Montori, V.M., 2010. Testosterone Therapy in Men with Androgen Deficiency Syndromes: An Endocrine Society Clinical Practice Guideline. J. Clin. Endocrinol. Metab. 95, 2536–2559. https://doi.org/10.1210/JC.2009-2354</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Bologna, M., Muzi, P., Biordi, L., Festuccia, C., Vicentini, C., 1995. Finasteride dose-dependently reduces the proliferation rate of the LnCap human prostatic cancer cell line in vitro. Urology 45, 282–290. https://doi.org/10.1016/0090-4295(95)80019-0</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Bowman, C.J., Barlow, N.J., Turner, K.J., Wallace, D.G., Foster, P.M.D., 2003. Effects of in Utero Exposure to Finasteride on Androgen-Dependent Reproductive Development in the Male Rat. Toxicol. Sci. 74, 393–406. https://doi.org/10.1093/TOXSCI/KFG128</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Chamberlain, N.L., Driver, E.D., Miesfeld, R.L., 1994. The length and location of CAG trinucleotide repeats in the androgen receptor N-terminal domain affect transactivation function. Nucleic Acids Res. 22, 3181. https://doi.org/10.1093/NAR/22.15.3181</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Costa, E.F., Domenice, S., Sircili, M., Inacio, M., Mendonca, B., 2012. DSD due to 5α-reductase 2 deficiency - From diagnosis to long term outcome. Semin. Reprod. Med. 30, 427–431. https://doi.org/10.1055/S-0032-1324727/ID/JR00766-20/BIB</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Dalton, J.T., Mukherjee, A., Zhu, Z., Kirkovsky, L., Miller, D.D., 1998. Discovery of nonsteroidal androgens. Biochem. Biophys. Res. Commun. 244, 1–4. https://doi.org/10.1006/bbrc.1998.8209</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Davey, R.A., Grossmann, M., 2016. Androgen Receptor Structure, Function and Biology: From Bench to Bedside. Clin. Biochem. Rev. 37, 3–15.</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Eder, I.E., Culig, Z., Putz, T., Nessler-Menardi, C., Bartsch, G., Klocker, H., 2001. Molecular Biology of the Androgen Receptor: From Molecular Understanding to the Clinic. Eur. Urol. 40, 241–251. https://doi.org/10.1159/000049782</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Grino, P.B., Griffin, J.E., Wilson, J.D., 1990. Testosterone at High Concentrations Interacts with the Human Androgen Receptor Similarly to Dihydrotestosterone. Endocrinology 126, 1165–1172. https://doi.org/10.1210/endo-126-2-1165</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Huggins, C., Hodges, C. V., 1941. Studies on prostatic cancer: I. The effect of castration, of estrogen and of androgen injection on serum phosphatases in metastatic carcinoma of the prostate. Cancer Res. 1, 293–297.</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Kang, Z., Pirskanen, A., Jänne, O.A., Palvimo, J.J., 2002. Involvement of proteasome in the dynamic assembly of the androgen receptor transcription complex. J. Biol. Chem. 277, 48366–48371. https://doi.org/10.1074/jbc.M209074200</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Keller, E.T., Ershler, W.B., Chang, C., 1996. The androgen receptor: a mediator of diverse responses. Front. Biosci. (Landmark Ed) 1, 59–71. https://doi.org/10.2741/A116</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Krotkiewski, M., Kral, J.G., Karlsson, J., 1980. Effects of castration and testosterone substitution on body composition and muscle metabolism in rats. Acta Physiol. Scand. 109, 233–237. https://doi.org/10.1111/J.1748-1716.1980.TB06592.X</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Lee, D.K., Chang, C., 2003. Expression and Degradation of Androgen Receptor: Mechanism and Clinical Implication. J. Clin. Endocrinol. Metab. 88, 4043–4054. https://doi.org/10.1210/JC.2003-030261</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Marks, L.S., 2004. 5Alpha-Reductase: History and Clinical Importance. Rev. Urol. 6 Suppl 9, S11-21.</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Nightingale, J., Chaudhary, K.S., Abel, P.D., Stubbs, A.P., Romanska, H.M., Mitchell, S.E., Stamp, G.W.H., Lalani, E.N., 2003. Ligand Activation of the Androgen Receptor Downregulates E-Cadherin-Mediated Cell Adhesion and Promotes Apoptosis of Prostatic Cancer Cells. Neoplasia 5, 347. https://doi.org/10.1016/S1476-5586(03)80028-3</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">OECD, 2020. Test No. 458: Stably Transfected Human Androgen Receptor Transcriptional Activation Assay for Detection of Androgenic Agonist and Antagonist Activity of Chemicals, OECD Guidelines for the Testing of Chemicals, Section 4. OECD Publishing, Paris. https://doi.org/10.1787/9789264264366-en</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Robitaille, J., Langlois, V.S., 2020. Consequences of steroid-5α-reductase deficiency and inhibition in vertebrates. Gen. Comp. Endocrinol. 290. https://doi.org/10.1016/j.ygcen.2020.113400</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Schaufele, F., Carbonell, X., Guerbadot, M., Borngraeber, S., Chapman, M.S., Ma, A.A.K., Miner, J.N., Diamond, M.I., 2005. The structural basis of androgen receptor activation: Intramolecular and intermolecular amino-carboxy interactions. Proc. Natl. Acad. Sci. U. S. A. 102, 9802–9807. https://doi.org/10.1073/pnas.0408819102</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Schuppe, E.R., Miles, M.C., Fuxjager, M.J., 2020. Evolution of the androgen receptor: Perspectives from human health to dancing birds. Mol. Cell. Endocrinol. 499, 110577. https://doi.org/10.1016/J.MCE.2019.110577</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Schwartz, C.L., Christiansen, S., Vinggaard, A.M., Axelstad, M., Hass, U., Svingen, T., 2019. Anogenital distance as a toxicological or clinical marker for fetal androgen action and risk for reproductive disorders. Arch. Toxicol. 93, 253–272. https://doi.org/10.1007/s00204-018-2350-5</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Supakar, P.C., Song, C.S., Jung, M.H., Slomczynska, M.A., Kim, J.M., Vellanoweth, R.L., Chatterjee, B., Roy, A.K., 1993. A novel regulatory element associated with age-dependent expression of the rat androgen receptor gene. J. Biol. Chem. 268, 26400–26408. https://doi.org/10.1016/S0021-9258(19)74328-2</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Tut, T.G., Ghadessy, F.J., Trifiro, M.A., Pinsky, L., Yong, E.L., 1997. Long Polyglutamine Tracts in the Androgen Receptor Are Associated with Reduced Trans-Activation, Impaired Sperm Production, and Male Infertility. J. Clin. Endocrinol. Metab. 82, 3777–3782. https://doi.org/10.1210/JCEM.82.11.4385</span></span></p>
<p style="margin-left:32px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif">Williams, A.J., Grulke, C.M., Edwards, J., McEachran, A.D., Mansouri, K., Baker, N.C., Patlewicz, G., Shah, I., Wambaugh, J.F., Judson, R.S., Richard, A.M., 2017. The CompTox Chemistry Dashboard: a community data resource for environmental chemistry. J. Cheminform. 9, 61. https://doi.org/10.1186/s13321-017-0247-6</span></span></p>
<p style="margin-left:32px"><span style="font-size:11.0pt"><span style="font-family:"Calibri",sans-serif">Wu, D., Lin, G., Gore, A.C., 2009. Age-related Changes in Hypothalamic Androgen Receptor and Estrogen Receptor </span></span><span style="font-size:11.0pt"><span style="font-family:"Calibri",sans-serif">α</span></span><span style="font-size:11.0pt"><span style="font-family:"Calibri",sans-serif"> in Male Rats. J. Comp. </span></span><span style="font-size:11.0pt"><span style="font-family:"Calibri",sans-serif">Neurol. 512, 688. https://doi.org/10.1002/CNE.21925</span></span></p>
2019-06-03T08:41:092023-10-19T08:22:211a167e3b-27fc-48a0-9db2-4b530efb144eef275245-bd24-4c5a-b011-9c46b6f6bdad2019-06-03T08:41:232019-06-03T08:41:23ef275245-bd24-4c5a-b011-9c46b6f6bdad996b18f8-8519-44e9-97e1-bd8d0470c10c2019-06-03T08:41:522019-06-03T08:41:52996b18f8-8519-44e9-97e1-bd8d0470c10cea76cdcc-6a0f-4f4a-a08b-67a1122dfb542019-06-03T08:42:052019-06-03T08:42:05Inhibition of 17α-hydrolase/C 10,20-lyase (Cyp17A1) activity leads to birth reproductive defects (cryptorchidism) in male (mammals)Cyp17A1 inhibition leads to undescended testes in mammals<p><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Bérénice Collet; Bart van der Burg</span></span></p>
<p><span style="font-size:14px"><span style="font-family:times new roman,times,serif">BioDetection Systems (</span></span><span style="font-size:12px"><span style="font-family:times new roman,times,serif">Science Park 406,1098 XH Amsterdam - The Netherlands)</span></span></p>
<p><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Corresponding author: berenice.collet@bds.nl; bart.van.der.burg@bds.nl</span></span></p>
Open for citation & comment<p style="text-align:justify"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">This Adverse Outcome Pathway describes the linkage between a decrease in 7α-hydroxylase/C17,20-lyase (Cyp17a1) activity and a specific reproductive malformation in male newborns : impaired testicular descent also called cryptorchidism.</span></span></p>
<p style="text-align:justify"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Cyp17a1 enzyme is known to mediate 17 alpha-hydroxylase and 17,20-lyase activities, the distinction between the two being functional and not genetic or structural. Mainly expressed in Leydig cells, this steroidogenic enzyme catalyzes the conversion of 17-OH-pregnenolone and 17-OH-progesterone to dehydroepiandrosterone (DHEA) and androstenediol, respectively. In that way, a decrease in Cyp17a1 activity would inevitably lead to a decline in both steroid precursors’ levels. As a result, this succession of key events will affect testosterone (T) and dihydrotestosterone (DHT) synthesis and circulating levels. A direct consequence to such a drop in major androgens levels would be a decline in androgen receptor activation, causing potential disturbances in development and maintenance of the male reproductive system such as cryptorchidism. To understand this AOP, it is important to notice that the second stage of the testicular descent process called “inguinoscrotal“ is an androgen-dependent event that can be dramatically affected by variations in androgenic activity.</span></span></p>
<p style="text-align:justify"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">The present AOP is linked to EU-ToxRisk Case Study 7: Read across evaluation of reproductive toxicity of conazoles. Conazoles are fungicide used in agriculture and as pharmaceuticals for treatment of human fungal diseases. They are known to act through inhibition of CYP51 which can be related to cross-reactivity with human enzymes involved in steroid metabolism, such as CYP17a1. In that respect, the proposed AOP and associated methods can be used as a basis to assess the effects of conazoles on steroidogenesis and reproductive development.</span></span></p>
<p style="text-align: justify;"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Abiraterone acetate used in androgen deprivation therapy<sup>4</sup> , antifungals from the conazoles family<sup>5</sup> (Ketonazole, Fadrozole, Imidazole, Prochloraz<sup>6</sup>…) etc.</span></span></p>
adjacentNot SpecifiedHighadjacentNot SpecifiedHighadjacentHighHighadjacentHighHighadjacentHighHighadjacentHighHighadjacentHighHighadjacentModerateModerateadjacentHighHigh<table border="0" cellpadding="0" cellspacing="0" style="width:1107px">
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Key Events</span></span></strong></td>
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">MIE</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Inhibition, Cyp17a1</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">CYP17a1 has a decisive function in steroidogenesis by constituting the initial step in a series of biochemical reactions.</span></span></td>
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE1</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Reduction, DHEA conversion</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">17-OH-pregnenolone is the direct precursor of dehydroepiandrosterone (DHEA). (Miller <em>et al</em>., 1988 - 2011)</span></span></td>
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<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">DHEA is the precursor of steroid hormones like testosterone and estradiol. </span></span></td>
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE2</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Reduction, Androstenedione conversion</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">17-OH-progesterone is the direct precursor of androstenedione. (Miller <em>et al</em>., 1988; Liu <em>et al.,</em> 2005)</span></span></td>
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<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Androstenedione is the precursor of steroid hormones like testosterone and estradiol.</span></span></td>
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE3</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Decrease, testosterone levels</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Reduction in testosterone synthesis leads to a reduction in testosterone circulating levels. (Miller <em>et al.,</em> 1988; Elder <em>et al.,</em> 1985; Shiraishi <em>et al.,</em> 2008)</span></span></td>
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE4</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Decrease, DHT levels</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Reduction in DHT synthesis leads to a reduction in DHT circulating levels. (Miller <em>et al.,</em> 1988 - 2011 1985; Shiraishi <em>et al.,</em> 2008)</span></span></td>
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE5</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Decrease, AR activation</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Androgen receptor activation is regulated by the binding of androgens. (Davey <em>et al.,</em> 2016; Gao <em>et al.,</em> 2005)</span></span></td>
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<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">AR activity can be decreased by either a lack of steroidal ligands (testosterone, DHT) or the presence of an antagonist.</span></span></td>
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE6</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Impaired inguinoscrotal phase</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Second phase of a two-step testis descent: the testis descends into the scrotum. (Hutson <em>et al.,</em> 2015)</span></span></td>
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<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Any impairment in testis migration will directly result in the absence of one or both testes from the scrotum.</span></span></td>
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">AOP</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Malformation, cryptorchidism</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Insertion of the testis in another position than the scrotum. (Hutson <em>et al., </em>2015a - 2015b; Boisen <em>et al.,</em> 2004; Acerini e<em>t al.,</em> 2009)</span></span></td>
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<td><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">How to measure</span></span></strong></td>
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<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Measurement in CYP17 MA-10 wild-type and CYP17 knock down MA-10 clone can be used to assess the effects of a dysfunction in CYP17a1 activity. (Liu <em>et al.,</em> 2005)</span></span></td>
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE1</span></span></strong></td>
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<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">17-OH-pregnenolone and DHEA can be fractionated using High Performance Liquid Chromatography. After separation, pregnenolone and DHEA levels can be quantify using immunoassay such as ELISA or Radio Immuno Assay (RIA). For both steroids, LC-MS/MS is also an option.</span></span></td>
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE2</span></span></strong></td>
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<p><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Competitive immunoenzymatic colorimetric methods (ELISA) for quantitative determination of 17-OH-progesterone and androstenedione concentration in serum or plasma are available. </span></span><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Progesterone and androstenedione synthesis can be monitored using radiolabeled steroid precursor in association with High Performance Liquid Chromatography (HPLC). During synthesis, steroids will incorporate the radioactive label which can be afterwards, used for quantification. First of all, HPLC combined with internal standards can be used for steroids collection, fractionation and identification. Once separated from the other steroids, progesterone and androstenedione can be finally quantified using liquid scintillation spectrometry.</span></span></p>
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE3</span></span></strong></td>
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<p><span style="font-family:times new roman,times,serif"><span style="font-size:14px">ELISA kit can be used for quantitative measurement of testosterone in various samples. Liquid Chromatography- tandem Mass Spectrometry is also an option. (Shiraishi <em>et al.,</em> 2008)</span></span></p>
<p><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Detection of increase and decrease in the production of testosterone after chemical exposure can be measured using the validated H295R Steroidogenesis Assay associated with hormone measurement kits (ELISA) and/or instrumental techniques (LC-MS). (OECD, 2011)</span></span></p>
<p><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Testosterone (T) levels in a sample can be measured by (High Performance) Liquid Chromatography. After sample fractionation, testosterone can be identified by comparison with internal standards spectrum. Quantification of T levels can be performed using hormones measurements kits (ELISA), instrumental techniques (LC-MS) or liquid scintillation spectrometry (after radiolabeling).</span></span></p>
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE4</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">DHT levels in a sample can be measured by (High Performance) Liquid Chromatography. After sample fractionation, DHT can be identify by comparison with internal standards spectrum. Quantification of DHT levels can be performed using hormones measurements kits (ELISA), instrumental techniques (LC-MS) or liquid scintillation spectrometry (after radiolabeling). (Shiraishi <em>et al.,</em> 2008)</span></span></td>
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<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE5</span></span></strong></td>
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<p>S<span style="font-family:times new roman,times,serif"><span style="font-size:14px">ignificance of AR signaling in fetal development can be studied through a conditional deletion of the androgen receptor using a Cre/loxP approach. The recommended animal model for reproductive study is the mouse. (Kaftanovskaya <em>et al.,</em> 2012)</span></span></p>
<p><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Also, epidemiological case-studies following mouse or humans expressing a complete androgen insensitivity allow to directly assess the effects of a lack of AR activation on the development. (Hutson 1985)</span></span></p>
<p><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Enzyme immunoassay (ELISA) kits for in vitro quantitative measurement of AR activity are available. Androgen receptors activity can be measured using bioassay such as the (Anti-)Androgen Receptor CALUX reporter gene assay. (van der Burg <em>et al.,</em> 2010)</span></span></p>
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</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE6</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-size:14px">-</span></td>
</tr>
<tr>
<td style="text-align:center"> </td>
<td> </td>
<td colspan="11"> </td>
</tr>
<tr>
<td><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">AOP</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Cryptorchidism is a birth defect that can be highlighted by a clinical examination. The aim of this palpation is to locate the gonad and determine its lowest position without causing painful traction on the spermatic cord. (Hutson <em>et al.,</em> 2015)</span></span></td>
</tr>
</tbody>
</table>
HighMaleHighDevelopmentModerateModerate<p><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><strong>Life Stage Applicability</strong></span></span></p>
<p><span style="font-size:14px"><span style="font-family:times new roman,times,serif">This AOP is relevant for developing male.</span></span></p>
<p><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><strong>Sex Applicability</strong></span></span></p>
<p><span style="font-size:14px"><span style="font-family:times new roman,times,serif">This AOP applies to males only.</span></span></p>
<table border="0" cellpadding="0" cellspacing="0" style="width:1107px">
<tbody>
<tr>
<td> </td>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Key Events</span></span></strong></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">MIE</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Inhibition, Cyp17a1</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">CYP17a1 has a decisive function in steroidogenesis by constituting the initial step in a series of biochemical reactions.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE1</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Reduction, DHEA conversion</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">17-OH-pregnenolone is the direct precursor of dehydroepiandrosterone (DHEA). (Miller <em>et al</em>., 1988 - 2011)</span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">DHEA is the precursor of steroid hormones like testosterone and estradiol. </span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE2</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Reduction, Androstenedione conversion</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">17-OH-progesterone is the direct precursor of androstenedione. (Miller <em>et al</em>., 1988; Liu <em>et al.,</em> 2005)</span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Androstenedione is the precursor of steroid hormones like testosterone and estradiol.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE3</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Decrease, testosterone levels</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Reduction in testosterone synthesis leads to a reduction in testosterone circulating levels. (Miller <em>et al.,</em> 1988; Elder <em>et al.,</em> 1985; Shiraishi <em>et al.,</em> 2008)</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE4</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Decrease, DHT levels</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Reduction in DHT synthesis leads to a reduction in DHT circulating levels. (Miller <em>et al.,</em> 1988 - 2011 1985; Shiraishi <em>et al.,</em> 2008)</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE5</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Decrease, AR activation</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Androgen receptor activation is regulated by the binding of androgens. (Davey <em>et al.,</em> 2016; Gao <em>et al.,</em> 2005)</span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">AR activity can be decreased by either a lack of steroidal ligands (testosterone, DHT) or the presence of an antagonist.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE6</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Impaired inguinoscrotal phase</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Second phase of a two-step testis descent: the testis descends into the scrotum. (Hutson <em>et al.,</em> 2015)</span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Any impairment in testis migration will directly result in the absence of one or both testes from the scrotum.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">AOP</span></span></strong></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Malformation, cryptorchidism</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Insertion of the testis in another position than the scrotum. (Hutson <em>et al., </em>2015a - 2015b; Boisen <em>et al.,</em> 2004; Acerini e<em>t al.,</em> 2009)</span></span></td>
</tr>
</tbody>
</table>
<p> </p>
<table border="0" cellpadding="0" cellspacing="0" style="width:1107px">
<tbody>
<tr>
<td> </td>
<td> </td>
<td><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">How to measure</span></span></strong></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">MIE</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Measurement in CYP17 MA-10 wild-type and CYP17 knock down MA-10 clone can be used to assess the effects of a dysfunction in CYP17a1 activity. (Liu <em>et al.,</em> 2005)</span></span></td>
</tr>
<tr>
<td style="text-align:center"> </td>
<td> </td>
<td colspan="11"> </td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE1</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">17-OH-pregnenolone and DHEA can be fractionated using High Performance Liquid Chromatography. After separation, pregnenolone and DHEA levels can be quantify using immunoassay such as ELISA or Radio Immuno Assay (RIA). For both steroids, LC-MS/MS is also an option.</span></span></td>
</tr>
<tr>
<td style="text-align:center"> </td>
<td> </td>
<td colspan="11"> </td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE2</span></span></strong></td>
<td> </td>
<td colspan="11">
<p><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Competitive immunoenzymatic colorimetric methods (ELISA) for quantitative determination of 17-OH-progesterone and androstenedione concentration in serum or plasma are available. </span></span><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Progesterone and androstenedione synthesis can be monitored using radiolabeled steroid precursor in association with High Performance Liquid Chromatography (HPLC). During synthesis, steroids will incorporate the radioactive label which can be afterwards, used for quantification. First of all, HPLC combined with internal standards can be used for steroids collection, fractionation and identification. Once separated from the other steroids, progesterone and androstenedione can be finally quantified using liquid scintillation spectrometry.</span></span></p>
</td>
</tr>
<tr>
<td style="text-align:center"> </td>
<td> </td>
<td colspan="11"> </td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE3</span></span></strong></td>
<td> </td>
<td colspan="11">
<p><span style="font-family:times new roman,times,serif"><span style="font-size:14px">ELISA kit can be used for quantitative measurement of testosterone in various samples. Liquid Chromatography- tandem Mass Spectrometry is also an option. (Shiraishi <em>et al.,</em> 2008)</span></span></p>
<p><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Detection of increase and decrease in the production of testosterone after chemical exposure can be measured using the validated H295R Steroidogenesis Assay associated with hormone measurement kits (ELISA) and/or instrumental techniques (LC-MS). (OECD, 2011)</span></span></p>
<p><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Testosterone (T) levels in a sample can be measured by (High Performance) Liquid Chromatography. After sample fractionation, testosterone can be identified by comparison with internal standards spectrum. Quantification of T levels can be performed using hormones measurements kits (ELISA), instrumental techniques (LC-MS) or liquid scintillation spectrometry (after radiolabeling).</span></span></p>
</td>
</tr>
<tr>
<td style="text-align:center"> </td>
<td> </td>
<td colspan="11"> </td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE4</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">DHT levels in a sample can be measured by (High Performance) Liquid Chromatography. After sample fractionation, DHT can be identify by comparison with internal standards spectrum. Quantification of DHT levels can be performed using hormones measurements kits (ELISA), instrumental techniques (LC-MS) or liquid scintillation spectrometry (after radiolabeling). (Shiraishi <em>et al.,</em> 2008)</span></span></td>
</tr>
<tr>
<td style="text-align:center"> </td>
<td> </td>
<td colspan="11"> </td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE5</span></span></strong></td>
<td> </td>
<td colspan="11">
<p>S<span style="font-family:times new roman,times,serif"><span style="font-size:14px">ignificance of AR signaling in fetal development can be studied through a conditional deletion of the androgen receptor using a Cre/loxP approach. The recommended animal model for reproductive study is the mouse. (Kaftanovskaya <em>et al.,</em> 2012)</span></span></p>
<p><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Also, epidemiological case-studies following mouse or humans expressing a complete androgen insensitivity allow to directly assess the effects of a lack of AR activation on the development. (Hutson 1985)</span></span></p>
<p><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Enzyme immunoassay (ELISA) kits for in vitro quantitative measurement of AR activity are available. Androgen receptors activity can be measured using bioassay such as the (Anti-)Androgen Receptor CALUX reporter gene assay. (van der Burg <em>et al.,</em> 2010)</span></span></p>
</td>
</tr>
<tr>
<td style="text-align:center"> </td>
<td> </td>
<td colspan="11"> </td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KE6</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-size:14px">-</span></td>
</tr>
<tr>
<td style="text-align:center"> </td>
<td> </td>
<td colspan="11"> </td>
</tr>
<tr>
<td><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">AOP</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Cryptorchidism is a birth defect that can be highlighted by a clinical examination. The aim of this palpation is to locate the gonad and determine its lowest position without causing painful traction on the spermatic cord. (Hutson <em>et al.,</em> 2015)</span></span></td>
</tr>
</tbody>
</table>
<table border="0" cellpadding="0" cellspacing="0" style="width:1057px">
<tbody>
<tr>
<td> </td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><strong>Key Event Relations</strong></span></span></td>
<td><span style="font-size:14px"><strong>General informations</strong></span></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td style="text-align:center"> </td>
<td style="text-align:center"> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><strong>KER1</strong></span></span></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Inhibition, Cyp17a1 - Reduction, DHEA conversion</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Cyp17a1 catalyzes the conversion of 17-OH-pregnenolone in DHEA through its 17α-hydroxylase activity. </span></span></td>
</tr>
<tr>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><strong>KER2</strong></span></span></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Inhibition, Cyp17a1 - Reduction, Androstenedione conversion</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Cyp17a1 catalyzes the cleavage of c17,20 bond of 17-OH-progesterone to give androstenedione.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><strong>KER3</strong></span></span></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Reduction, DHEA/Androstenedione - Decrease, testosterone</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Levels of two main testosterone precursors (DHEA and androstenedione) are decreased (KE1-KE2) </span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Deficiency in these intermediate steroids directly lead to a reduction in testosterone synthesis.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><strong>KER4</strong></span></span></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Decrease, testosterone levels - Decrease, DHT levels</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Testosterone being the precursor of DHT, a reduction in its synthesis/levels directly affects this metabolite.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><strong>KER5</strong></span></span></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Decrease, testosterone levels - Decrease, AR activation</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">A lack in androgenic hormones (either testosterone or DHEA) results in a diminution of AR activation.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><strong>KER6</strong></span></span></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Decrease, AR activation - Impaired inguinoscrotal phase</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">A dysfunction in androgens synthesis and AR activation leads to a defect in the inguinoscrotal stage.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><strong>AOP</strong></span></span></td>
<td style="text-align:center"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Impaired inguinoscrotal phase - Malformation, cryptorchidism</span></span></td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">A defect in the inguinoscrotal stage leads to an impairment in the testis descent to the scrotum. </span></span></td>
</tr>
</tbody>
</table>
<p> </p>
<table border="0" cellpadding="0" cellspacing="0" style="width:1498px">
<tbody>
<tr>
<td> </td>
<td style="text-align:center"><strong><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Key Event Relations</span></span></strong></td>
<td colspan="12"><strong><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Biological plausibility</span></span></strong></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-family:times new roman,times,serif"><span style="font-size:14px">KER1</span></span></strong></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Inhibition, Cyp17a1 - Reduction, DHEA conversion</span></span></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">High</span></span></td>
<td colspan="11"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Cyp17a1 is known to cleave the c17,20bond of 10-OH-pregnenolone through its 17α-hydroxylase activity.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-family:times new roman,times,serif"><span style="font-size:14px">KER2</span></span></strong></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Inhibition, Cyp17a1 - Reduction, Androstenedione conversion</span></span></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">High</span></span></td>
<td colspan="11"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Most of androstenedione is synthesized through the 17,20-lyase activity of Cyp17a1.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-family:times new roman,times,serif"><span style="font-size:14px">KER3</span></span></strong></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Reduction, DHEA/Androstenedione - Decrease, testosterone</span></span></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">High</span></span></td>
<td colspan="11"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">This steroid can be synthesized from either DHEA/Androstenediol or Androstenedione both catalyzed by the 3β-hydroxysteroid dehydrogenase enzyme.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-family:times new roman,times,serif"><span style="font-size:14px">KER4</span></span></strong></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Decrease, testosterone levels - Decrease, DHT levels</span></span></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">High</span></span></td>
<td colspan="11"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Testosterone is converted to DHT by 5alpha-reductase.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-family:times new roman,times,serif"><span style="font-size:14px">KER5</span></span></strong></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Decrease, testosterone levels - Decrease, AR activation</span></span></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">High</span></span></td>
<td colspan="11"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">AR is a ligand-dependent nuclear transcription factor. Its activation is known to be mediated by Testosterone and DHT.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-family:times new roman,times,serif"><span style="font-size:14px">KER6</span></span></strong></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Decrease, AR activation - Impaired inguinoscrotal phase</span></span></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Moderate</span></span></td>
<td colspan="11"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Although causes of cryptorchidism are not well-established, androgens are known to play an important role in the inguinoscrotal testicular descent</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-family:times new roman,times,serif"><span style="font-size:14px">KER6</span></span></strong></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Decrease, AR activation - Impaired inguinoscrotal phase</span></span></td>
<td> </td>
<td colspan="11"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">in both animals and humans. Variation affecting androgens levels and AR activation directly lead to defect in the inguinoscrotal phase of testis descent. </span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-family:times new roman,times,serif"><span style="font-size:14px">AOP</span></span></strong></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Impaired inguinoscrotal phase - Malformation, cryptorchidism</span></span></td>
<td style="text-align:center"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">High</span></span></td>
<td colspan="11"><span style="font-family:times new roman,times,serif"><span style="font-size:14px">Any impairment affecting thie inguinoscrotal phase has direct repercussion on proper testis descent.</span></span></td>
</tr>
</tbody>
</table>
<p> </p>
<table border="0" cellpadding="0" cellspacing="0" style="width:1181px">
<tbody>
<tr>
<td style="text-align:center"> </td>
<td> </td>
<td colspan="11"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Empirical support</span></span></strong></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KER1</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">In 2005, Liu Y., Yao ZX., and Papadopoulos V. showed that MA-10 CYP17 knock down cells synthesize much less </span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">pregnenolone and DHEA compared with MA-10 wild type cells.</span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><a href="https://doi.org/10.1210/me.2004-0271">https://doi.org/10.1210/me.2004-0271 </a></span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KER2</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Using MA-10 CYP17 knock down cells, Liu Y., Yao ZX., and Papadopoulos V. showed that cells without CYP17 enzyme</span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"> tend to synthesize less progesterone than MA-10 wild type cells.</span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><a href="https://doi.org/10.1210/me.2004-0271">https://doi.org/10.1210/me.2004-0271 </a></span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KER3</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">-</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KER4</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">An enzyme immunoassay such as ELISA kit can be used for quantitative determination of DHT levels.</span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">The ratio of serum testosterone to serum DHT shows the general activity of 5-alpha reductase.</span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KER5</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Norris J.D., et al. highlighted that CYP17 inhibition using lyase–selective inhibitor antagonize AR activation.</span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><a href="https://doi.org/10.1172/JCI87328">https://doi.org/10.1172/JCI87328 </a></span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">KER6</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">In 1985, Hutson studied both mice model and humans expressing a complete androgen insensitivity. This particular</span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">research demonstrated that in such case, the testis remains in the inguinal canal or groin.</span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><a href="http://dx.doi.org/10.1016/S0140-6736(85)92739-4">http://dx.doi.org/10.1016/S0140-6736(85)92739-4 </a></span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="9"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Kaftanovskaya<em> et al.</em> confirmed the previous statement in 2012 using a Cre-loxP approach study</span></span></td>
<td> </td>
<td> </td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><a href="https://doi.org/10.1210/me.2011-1283">https://doi.org/10.1210/me.2011-1283 </a></span></span></td>
</tr>
<tr>
<td style="text-align:center"><strong><span style="font-size:14px"><span style="font-family:times new roman,times,serif">AOP</span></span></strong></td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Kaftanovskaya <em>et al. </em>research are based on conditional deletion of the androgen receptor using a Cre/loxP approach in male mice. </span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Study from 2012 showed that a depletion of the AR in the gubernaculum leads to an impairment in inguinoscrotal phase and induces cryptorchidism. </span></span></td>
</tr>
<tr>
<td> </td>
<td> </td>
<td colspan="11"><span style="font-size:14px"><span style="font-family:times new roman,times,serif"><a href="https://doi.org/10.1210/me.2011-1283">https://doi.org/10.1210/me.2011-1283 </a></span></span></td>
</tr>
</tbody>
</table>
<p>-</p>
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<p><span style="font-size:14px"><span style="font-family:times new roman,times,serif">Vinggaard A.M., Christiansen S., Laier P., Poulsen M.E., Breinholt V, Jarfelt K., Jacobsen H., Dalgaard M., Nellemann C. and Hass U. (2005) Perinatal exposure to the fungicide prochloraz feminizes the male rat offspring. Toxicological Sciences, 85:886–897<a href="https://www.google.com/url?q=https://doi.org/10.1093/toxsci/kfi150&sa=D&ust=1559634365166000">https://doi.org/10.1093/toxsci/kfi150</a> </span></span></p>
<p> </p>
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