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Relationship: 2076


A descriptive phrase which clearly defines the two KEs being considered and the sequential relationship between them (i.e., which is upstream, and which is downstream). More help

Decreased, 11KT leads to Impaired, Spermatogenesis

Upstream event
The causing Key Event (KE) in a Key Event Relationship (KER). More help
Downstream event
The responding Key Event (KE) in a Key Event Relationship (KER). More help

Key Event Relationship Overview

The utility of AOPs for regulatory application is defined, to a large extent, by the confidence and precision with which they facilitate extrapolation of data measured at low levels of biological organisation to predicted outcomes at higher levels of organisation and the extent to which they can link biological effect measurements to their specific causes.Within the AOP framework, the predictive relationships that facilitate extrapolation are represented by the KERs. Consequently, the overall WoE for an AOP is a reflection in part, of the level of confidence in the underlying series of KERs it encompasses. Therefore, describing the KERs in an AOP involves assembling and organising the types of information and evidence that defines the scientific basis for inferring the probable change in, or state of, a downstream KE from the known or measured state of an upstream KE. More help

AOPs Referencing Relationship

AOP Name Adjacency Weight of Evidence Quantitative Understanding Point of Contact Author Status OECD Status
PPARalpha Agonism Leading to Decreased Viable Offspring via Decreased 11-Ketotestosterone adjacent High Low Jennifer Olker (send email) Open for citation & comment
Inhibition of 11β-Hydroxysteroid Dehydrogenase leading to decreased population trajectory adjacent High Moderate Young Jun Kim (send email) Under development: Not open for comment. Do not cite Under Development

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KER.In general, this will be dictated by the more restrictive of the two KEs being linked together by the KER.  More help
Term Scientific Term Evidence Link
teleost fish teleost fish High NCBI

Sex Applicability

An indication of the the relevant sex for this KER. More help
Sex Evidence
Male High

Life Stage Applicability

An indication of the the relevant life stage(s) for this KER.  More help
Term Evidence
Adult, reproductively mature High

Key Event Relationship Description

Provides a concise overview of the information given below as well as addressing details that aren’t inherent in the description of the KEs themselves. More help

Androgens are critical for maintaining the normal male reproductive system (Tang, H., et al. 2018). Of these androgens, 11-KT has been identified as the most important in teleost fish (Borg, B. 1994). 11-KT is produced by the cyp11c1 encoded enzyme, 11ß-hydroxylase (Zheng, et al. 2020). 11-KT has been shown to bind to the androgen receptor with similar affinity as testosterone in zebrafish (Jorgensen, et al. 2007). It is well documented that 11-KT is involved in spermatogenesis, spermiation, male secondary sexual characteristics, and breeding behaviors (Geraudie, P. et al. 2010; Amer, M.A. et al. 2001). 11-KT is needed for the inducement of spermatogenesis and sperm production in teleost fish, with 10 ng/ml 11-KT being sufficient to induce full spermatogenesis in the Japanese eel (Miura, C. and T. Miura 2011). The mechanism through which 11-KT induces spermatogenesis is believed to be via activation of Sertoli cells and activin B (Miura et al. 2011; Miura et al. 2001; Sales, C.F., et al. 2020; Cavaco J.E.B., et al. 1998). 11-KT is not responsible for the acquisition of sperm motility in salmonids (Miura, et al. 1992).

Evidence Collection Strategy

Include a description of the approach for identification and assembly of the evidence base for the KER. For evidence identification, include, for example, a description of the sources and dates of information consulted including expert knowledge, databases searched and associated search terms/strings.  Include also a description of study screening criteria and methodology, study quality assessment considerations, the data extraction strategy and links to any repositories/databases of relevant references.Tabular summaries and links to relevant supporting documentation are encouraged, wherever possible. More help

Evidence Supporting this KER

Addresses the scientific evidence supporting KERs in an AOP setting the stage for overall assessment of the AOP. More help

Table 2. Effect of either 11-ketotestosterone (11-KT) treatment or increased testicular production/plasma concentrations of 11-KT on spermatogenesis. 


Experimental design 

11-KT treatment or response 

Spermatogenesis effect 


(+) 1

Spermatogenesis (+) 1


Senegalese sole (Solea senegalensis

Treated with saline (control) or with 50 μg/kg GnRHa, with or without another implant containing 2 or 7 mg/kg 11-ketoandrostenedione for 28 days

Fish treated with GnRHa + OA saw increased 11-KT levels compared to control and GnRHa alone 

Fish treated with GnRHa + OA saw lower number of spermatogonia and spermatocytes and a higher number of spermatids than those of GnRHa or control 



Agulleiro, M.J., et al. 2007 

Japanese huchen (Hucho perryi

Incubated immature testis fragments 

10 ng/ml for 15 days 

BrdU (proliferation marker) index reached 34.5% ± 1.7%; percentage of late type B spermatogonia reached about 7.5% compared to 0% in control



Amer, M.A. et al. 2001 


African catfish (Clarias gariepinus

Juvenile male catfish implanted with pellets containing 30 μg/g body weight of 11-KT

30 μg/g body weight of 11-KT; plasma 11-KT levels reached 8.3 ± 0.6 ng/ml after 2 weeks 

GSI increased compared to control; testicular stage 1 (contain spermatogonia only) and 2 (contain spermatogonia and spermatocytes) increased from about 90% stage 1 and 10% stage 2 in end control to about 25% stage 1 and 75% stage 2 



Cavaco, J.E.B. et al. 2001 


African catfish (Clarias gariepinus



Male catfish at beginning of spermatogenesis implanted with pellets containing 30 μg/g body weight of 11-KT 

Plasma 11-KT levels reached 6.1 ± 0.8 ng/ml after 2 weeks 

Testicular stages changed from about 65% stage 1 and 35% stage 2 in the end control to about 65% stage 2 and 35% stage 3 (contain spermatogonia, spermatocytes and spermatids)



Cavaco J.E.B., et al. 1998 



Male catfish at beginning of spermatogenesis implanted with pellets containing 30 μg/g body weight of 11β-hydroxyandrostenedione 

Plasma 11-KT levels reached 7.3 ± 0.7 ng/ml after 2 weeks 

Testicular stages changed from about 65% stage 1 and 35% stage 2 in the end control to about 55% stage 2 and 40% stage 3 



Male catfish at beginning of spermatogenesis implanted with pellets containing 30 μg/g body weight of androstenetrione

Plasma 11-KT levels reached 2.4 ± 0.3 ng/ml after 2 weeks 

Testicular stages changed from about 65% stage 1 and 35% stage 2 in the end control to about 50% stage 2 and 50% stage 3  



Atlantic salmon (Salmo salar

Immature fish injected with 25 μg adrenosterone/g of body weight 

After 7 and 14 days, 11-KT plasma levels significantly increased compared to control (7 days post-treatment were higher) 

5-fold higher number of type A differentiated spermatogonia than control fish after 14 days (7-day samples lost - no data) 



Melo, M.C. et al. 2015 

Japanese eel (Anguilla japonica





Immature testes were removed and cultured in medium with varying levels of 11-KT 





0.01 ng/ml 11-KT for 15 days 

No effect 



Miura, T., et al. 1991 





0.1 ng/ml 11-KT for 15 days 

No effect 



1 ng/ml 11-KT for 15 days 

No effect 



10 ng/ml 11-KT for 15 days 

Mitosis occurred in 50-60% of cysts (as effective as 100 ng/ml 11-KT treatment) 



100 ng/ml 11-KT for 15 days 

Mitosis occurred in 50-60% of cysts (as effective as 10 ng/ml 11-KT treatment) 



Japanese eel (Anguilla japonica




Immature testis fragments cultured in media with 11-KT for up to 36 days 




10 ng/ml of 11-KT for 9 days 

Began mitotic division; produced late-type B spermatogonia 



Miura, T., et al. 1991 




10 ng/ml of 11-KT for 18 days 

Produced zygotene spermatocytes from meiotic prophase 



10 ng/ml of 11-KT for 21 days 

Spermatids and spermatozoa observed 



10 ng/ml of 11-KT for 36 days 

All stages of germ cells present 



Chub mackerel (Scomber japonicus

Peptide mix containing synthetic peptides corresponding to chub mackerel Kiss1-15 at a final concentration of 250 ng/g fish were injected 3 times at 2-week interval (immature adult)

Treated fish showed significantly higher 11-KT levels 

Significantly higher levels of spermatids and spermatozoa



Selvaraj, S., et al. 2013 

Japanese eel

(Anguilla japonica)

Testicular fragment treated with 0.01 ng/ml cortisol 

No significant change in 11-KT production compared to control 

Nonsignificant increase in BrdU Index compared to control 



Ozaki, Y., et al. 2006

Testicular fragment treated with 0.1 ng/ml cortisol 

No significant change in 11-KT production compared to control 

Significant increase in BrdU Index compared to control 



Testicular fragment t

treated with 1 ng/ml cortisol 

Nonsignificant, slight increase in 11-KT production compared to control 

Significant increase in BrdU Index compared to control 



Testicular fragment treated with 10 ng/ml cortisol 

Nonsignificant increase in 11-KT production compared to control 

Significant increase in BrdU Index compared to control 



Testicular fragment treated with 100 ng/ml cortisol 

Significant increase in 11-KT production compared to control 

Significant increase in BrdU Index compared to control 




(Danio rerio) 

cyp11c1 knockout rescue via 11-ketoandrostenedione (11-KA) treatment 

100 nM 11-KA for 4 hours per day for 10 days 

Promoted the juvenile ovary-to-testis transition; genes associated with Leydig cell development/function restored; increased sperm volume 



Zhang, Q., et al. 2020 

1 (+) represents an effect on the key event has been established.

Biological Plausibility
Addresses the biological rationale for a connection between KEupstream and KEdownstream.  This field can also incorporate additional mechanistic details that help inform the relationship between KEs, this is useful when it is not practical/pragmatic to represent these details as separate KEs due to the difficulty or relative infrequency with which it is likely to be measured.   More help

It is well known that 11-KT is a critical androgen for proper male reproduction in teleost fish. The males' primary reproductive role is to fertilize the oocytes.

Seasonal changes in 11-KT are correlated with cyclic spermatogenesis events in teleosts (Basak, R., et al. 2016). In many teleost fish, 11-KT levels peak at spawning (see Table 1 below).

11-KT is proposed to induce spermatogenesis via the activation of Sertoli cells, which in turn regulates factors including activin B (Miura et al. 2011; Miura et al. 2001). Activin B stimulates spermatogonial proliferation (Sales, C.F., et al. 2020; Cavaco J.E.B., et al. 1998).

Zhang et al. (2020) showed that zebrafish with cyp11c1 knockout have reduced 11-KT levels, smaller genitalia, inability naturally mate, defective Leydig and Sertoli cells, and insufficient spermatogenesis. This is corrected by treatment of 100 nM 11-KA (which is converted to 11-KT in vivo) for 4 hours per day for 10 days. This shows that spermatogenesis was arrested due to insufficient 11-KT levels.


Table 1. Plasma concentrations of 11-KT peak during spawning and decline shortly after in a variety of species.


Scientific name 

Reproductive strategy 1


Japanese huchen 

Hucho perryi 


Amer et al., 2001 


Huso huso L. female x Acipenser ruthenus L. male 


Amiri et al., 1996 

Spotted snakehead  

Channa punctatus 


Basak et al., 2016 


Cichlasoma dimerus 


Birba et al., 2015 

Largemouth bass 

Micropterus salmoides salmoides 


Brown et al., 2019 

Chinook salmon 

Oncorhynchus tshawytscha 


Campbell et al., 2003 

Gilthead seabream 

Sparus aurata L. 


Chaves-Pozo et al., 2008 


Fundulus heteroclitus 


Cochran, 1987 

Eastern Mosquitofish  

Gambusia holbrooki 


Edwards et al., 2013 

Rainbow trout 

Salmo gairdneri 


Fostier et al., 1984 

Senegalese sole 

Solea senegalensis 


García-López et al., 2006 


Rutilus rutilus 


Geraudine et al., 2010 


Acipenser ruthenus 


Golpour et al., 2017 


Anoplopoma fimbria 


Guzmán et al., 2018 

Brook trout 

Salvelinus fontinalis 


de Montgolfier et al., 2009 


Scophthalmus rhombus L. 


Hachero-Cruzado et al., 2012 

Three-spined stickleback 

Gasterosteus aculeatus 


Hellqvist et al., 2006 

Red-spotted grouper 

Epinephelus akaara 


Li et al., 2007 

Japanese dace 

Tribolodon hakonesis 


Ma et al., 2005 


Stizostedion vitreum 


Malison et al., 1994 

Florida gar 

Lepisosteus platyrhincus 


Orlando et al., 2003 

Chum Salmon 

Oncorhynchus keta 


Onuma et al., 2009 

Hornyhead Turbot 

Pleuronichthys verticalis 


Reyes et al., 2012 

Golden mahseer 

Tor putitora 


Shahi et al., 2015 

Plainfin midshipman 

Porichthys notatus 


Sisneros et al., 2004 

Amago salmon 

Oncorhynchus rhodurus 


Ueda et al., 1983; Sakai et al., 1989 

Atlantic halibut 

Hippoglossus hippoglossus L.  


Weltzien et al., 200

  1 Defined as single spawning species (spawn once/year) or multiple spawning species (spawn multiple clutches of eggs per reproductive period).



Uncertainties and Inconsistencies
Addresses inconsistencies or uncertainties in the relationship including the identification of experimental details that may explain apparent deviations from the expected patterns of concordance. More help

In a study by Hatef, A. et al. (2012), treatment with the anti-androgen vinclozolin at 100 μg/L saw an increase in 11-KT levels with no significant change to spermatogenesis. This is consistent with other studies provided. Additionally, treatment at 400 μg/L saw no significant change in 11-KT levels with a decrease in spermatogenesis (although this decrease may not be statistically significant). The reason for these increases in 11-KT remains unknown; however, it is hypothesized that it is due to competitive androgen receptor binding.

Ozaki et al. (2006) showed that treatment with 100 ng/ml of cortisol significantly increased 11-KT levels. However, the less concentrated doses only saw non-significant increases in 11-KT with significant increases in spermatogenesis observed in all but the lowest dose. Despite this, Ozaki et al. make the generalization that cortisol treatment increased 11-KT and, in turn, spermatogenesis.

The study by Runnalls et al. (2007) saw treatment with Clofibric acid caused no significant changes to 11-KT levels, but that the levels did appear lower. Additionally, these treatments saw no significant effect on sperm number, but did see a significant increase in the number of non-viable sperm.

In a study by Zhang, Q., et al. (2020), cyp11c1 knockout did not completely block spermatogenesis. Zhang et al. explain this could be due to other androgens (11β-hydroxyandrostenedione and testosterone) compensating for the reduction in 11-KT, as they can both bind to the androgen receptor to influence downstream signaling.

Known modulating factors

This table captures specific information on the MF, its properties, how it affects the KER and respective references.1.) What is the modulating factor? Name the factor for which solid evidence exists that it influences this KER. Examples: age, sex, genotype, diet 2.) Details of this modulating factor. Specify which features of this MF are relevant for this KER. Examples: a specific age range or a specific biological age (defined by...); a specific gene mutation or variant, a specific nutrient (deficit or surplus); a sex-specific homone; a certain threshold value (e.g. serum levels of a chemical above...) 3.) Description of how this modulating factor affects this KER. Describe the provable modification of the KER (also quantitatively, if known). Examples: increase or decrease of the magnitude of effect (by a factor of...); change of the time-course of the effect (onset delay by...); alteration of the probability of the effect; increase or decrease of the sensitivity of the downstream effect (by a factor of...) 4.) Provision of supporting scientific evidence for an effect of this MF on this KER. Give a list of references.  More help
Response-response Relationship
Provides sources of data that define the response-response relationships between the KEs.  More help

Decreases in 11-KT levels were also seen with decreases in spermatogenesis in several studies (see table above).

10 ng/ml of 11-KT has been shown to be needed to induce full spermatogenesis in Japanese eel (Amer, M.A. et al. 2001; Miura, C. et al. 2011).

Information regarding the approximate time-scale of the changes in KEdownstream relative to changes in KEupstream (i.e., do effects on KEdownstream lag those on KEupstream by seconds, minutes, hours, or days?). More help
Known Feedforward/Feedback loops influencing this KER
Define whether there are known positive or negative feedback mechanisms involved and what is understood about their time-course and homeostatic limits. More help

Domain of Applicability

A free-text section of the KER description that the developers can use to explain their rationale for the taxonomic, life stage, or sex applicability structured terms. More help


11-KT is the main androgen in teleost fish (Borg, B. 1994).

Sex Applicability:

11-KT is present in both male and female fish; however, spermatogenesis is a male-specific process.

Life Stage Applicability:

Spermatogenesis is observable in male fish that have reached the reproductive stage.


List of the literature that was cited for this KER description. More help


Agbohessi, P.T., Imorou Toko I., Ouédraogo, A., Jauniaux, T., Mandiki, S.N., & Kestemont, P. (2014). Assessment of the health status of wild fish inhabiting a cotton basin heavily impacted by pesticides in Benin (West Africa). Science of the Total Environment, 506-507, 567-584.

Agulleiro, M.J., Scott, A.P., Duncan, N., Mylonas, C.C., & Cerdà, J. (2007). Treatment of GnRHa-implanted Senegalese sole (Solea senegalensis) with 11-ketoandrostenedione stimulates spermatogenesis and increases sperm motility. Comparative Biochemistry and Physiology Part A: Molecular and Integrative Physiology, 147(4), 885-92.

Amer, M.A., Miura, T., Miura, C., & Yamauchi, K. (2001). Involvement of Sex Steroid Hormones in the Early Stages of Spermatogenesis in Japanese Huchen (Hucho perryi ). Biology of Reproduction, 65(4), 1057–1066.

Amiri, B.M., Maebayashi, M., Adachi, S., & Yamauchi, K. (1996). Testicular development and serum sex steroid profiles during the annual sexual cycle of the male sturgeon hybrid the bester. Journal of Fish Biology, 48(6), 1039-1050.

Aoki, K.A., Harris, C.A., Katsiadaki, I., & Sumpter, J.P. (2011). Evidence suggesting that di-n-butyl phthalate has antiandrogenic effects in fish. Environmental Toxicology and Chemistry, 30(6), 1338-1345.

Baatrup, E. & Junge, M. (2001). Antiandrogenic pesticides disrupt sexual characteristics in the adult male guppy Poecilia reticulata. Environmental Health Perspectives, 109(10), 1063-70. DOI: 10.1289/ehp.011091063

Basak, R., Roy, A. & Rai, U. (2016). Seasonality of reproduction in male spotted murrel Channa punctatus: correlation of environmental variables and plasma sex steroids with histological changes in testis. Fish Physiology and Biochemistry, 42(5), 1249-1258.

Berglund, I., Antonopoulou, E., Mayer, I., & Borg, B. (1995). Stimulatory and inhibitory effects of testosterone on testes in Atlantic salmon male parr. Journal of Fish Biology, 47(4), 586-598.

Bhandari, R.K., Alam, M.A., Soyano, K., & Nakamura, M. (2006). Induction of female-to-male sex change in the honeycomb grouper (Epinephelus merra) by 11-ketotestosterone treatments. Zoological Science, 23(1), 65-69.

Birba, A., Ramallo, M.R., Nostro, F.L., Moreira, R.G., & Pandolfi, M. (2015). Reproductive and parental care physiology of Cichlasoma dimerus males. General and Comparative Endocrinology, 15, 193-200.

Borg, B. (1994). Androgens in teleost fishes. Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology, and Endocrinology, 109(3), 219-245.

Brown, M.L., Kasiga, T., Spengler, D.E., & Clapper, J.A. (2019). Reproductive cycle of northern largemouth bass Micropterus salmoides salmoides. Journal of Experimental Zoology Part A: Ecological and Integrative Physiology, 331(10), 540-551.

Campbell, B., Dickey, J.T., & Swanson, P. (2003). Endocrine changes during onset of puberty in male spring Chinook salmon, Oncorhynchus tshawytscha. Biology of Reproduction, 69(6), 2109-2117.

Cavaco, J.E.B., Bogerd, J., Goos, H., & Schulz, R.W. (2001). Testosterone inhibits 11-ketotestosterone-induced spermatogenesis in African catfish (Clarias gariepinus). Biology of Reproduction, 65(6), 1807-1812.

Cavaco, J.E.B., Vilrokx, C., Trudeau, V.L., Schulz, R.W., & Goos, H.J.T. (1998). Sex steroids and the initiation of puberty in male African catfish, Clarias gariepinus. American Journal of Physiology, 275(6), 1793-1802.

Chauvigné, F., Parhi, J., Ollé, J., & Cerdà, J. (2017). Dual estrogenic regulation of the nuclear progestin receptor and spermatogonial renewal during gilthead seabream (Sparus aurata) spermatogenesis. Comparative Biochemistry and Physiology Part A: Molecular and Integrative Physiology, 206, 36-46.

Chaves-Pozo, E., Arjona, F.J., García-López, A., García-Alcázar, A., Meseguer, J., & García-Ayala A. (2008). Sex steroids and metabolic parameter levels in a seasonal breeding fish (Sparus aurata L.). General and Comparative Endocrinology, 156(3), 531-536.

Chen, J., Jiang, D., Tan, D., Fan, Z., Wei, Y., Li, M., & Wang, D. (2017). Heterozygous mutation of eEF1A1b resulted in spermatogenesis arrest and infertility in male tilapia, Oreochromis niloticus. Scientific Reports, 7, 43733.

Cochran, R.C. (1987). Serum androgens during the annual reproductive cycle of the male mummichog, Fundulus heteroclitus. General and Comparative Endocrinology, 65(1), 141-148.

de Montgolfier, B., Faye, A., Audet, C., & Cyr, D.G. (2009). Seasonal variations in testicular connexin levels and their regulation in the brook trout, Salvelinus fontinalis. General and Comparative Endocrinology, 162(3), 276-285.

de Waal, P.P., Leal, M.C., García-López, A., Liarte, S., de Jonge, H., Hinfray, N., Brion, F., Schulz, R.W., & Bogerd, J. (2009). Oestrogen-induced androgen insufficiency results in a reduction of proliferation and differentiation of spermatogonia in the zebrafish testis. Journal of Endocrinology, 202(2), 287-97.

Delvin, R.H. & Nagahama, Y. (2002). Sex determination and sex differentiation in fish: an overview of genetic, physiological, and environmental influences. Aquaculture, 208(3-4), 191-364.

Edwards, T.M., Miller, H.D., Toft, G., & Guillette, L.J. Jr. (2013). Seasonal reproduction of male Gambusia holbrooki (eastern mosquitofish) from two Florida lakes. Fish Physiology and Biochemistry, 39(5), 1165-1180.

Fostier, A., Billard, R., & Breton, B. (1984). Plasma 11-oxotestosterone and gonadotrophin in relation to the arrest of spermiation in rainbow trout (Salmo gairdneri). General and Comparative Endocrinology, 54(3), 378–381. DOI: 10.1016/0016-6480(84)90150-3

Fostier, A., Billard, R., & Breton, B. (1984). Plasma 11-oxotestosterone and gonadotrophin in relation to the arrest of spermiation in rainbow trout (Salmo gairdneri). General and Comparative Endocrinology, 54(3), 378-381. DOI: 10.1016/0016-6480(84)90150-3

García-López, A., Fernández-Pasquier, V., Couto, E., Canario, A.V., Sarasquete, C., & Martínez-Rodríguez, G. (2006). Testicular development and plasma sex steroid levels in cultured male Senegalese sole Solea senegalensis Kaup. General and Comparative Endocrinology, 147(3), 343-351.

Geraudie, P., Gerbron, M., & Minier, C. (2010). Seasonal variations and alterations of sex steroid levels during the reproductive cycle of male roach (Rutilus rutilus). Marine Environmental Research, 69(S1), S53-S55.

Golpour, A., Broquard, C., Milla, S., Dadras, H., Baloch, A.R., Saito, T., & Pšenička, M. (2017). Gonad histology and serum 11-KT profile during the annual reproductive cycle in sterlet sturgeon adult males, Acipenser ruthenus. Reproduction in Domestic Animals, 52(2), 319-326.

Golshan, M. & Alavi, S.M.H. (2019). Androgen signaling in male fishes: Examples of anti-androgenic chemicals that cause reproductive disorders. Theriogenology, 139, 58-71.

Golshan, M. & Alvai S.M.H. (2019). Androgen signaling in male fishes: Examples of anti-androgenic chemicals that cause reproductive disorders. Theriogenology, 139, 58-71.

Guzmán, J.M., Luckenbach, J.A., da Silva, D.A.M., Hayman, E.S., Ylitalo, G.M., Goetz, F.W., & Swanson, P. (2018). Seasonal variation of pituitary gonadotropin subunit, brain-type aromatase and sex steroid receptor mRNAs, and plasma steroids during gametogenesis in wild sablefish. Comparative Biochemistry and Physiology Part A: Molecular Integrated Physiology, 219-220, 48-57.

Hachero-Cruzado, I., Forniés, A., Herrera, M., Mancera, J.M., & Martínez-Rodríguez, G. (2012). Sperm production and quality in Brill scophthalmus rhombus L.: Relation to circulating sex steroid levels. Fish Physiology and Biochemistry, 39(2), 215-220.

Hatef, A., Alavi, S.M.H., Milla, S., Křišťan, J., Golshan, M., Fontaine, P., & Linhart, O. (2012). Anti-androgen vinclozolin impairs sperm quality and steroidogenesis in goldfish. Aquatic Toxicology, 122-123, 181-187.

Hellqvist, A., Schmitz, M., Mayer, I., & Borg, B. (2006). Seasonal changes in expression of LH-beta and FSH-beta in male and female three-spined stickleback, Gasterosteus aculeatus. General and Comparative Endocrinology, 145(3), 263-269.

Idler, D.R., Bitners, I.I., & Schmidt, P.J. (1961). 11-KETOTESTOSTERONE: AN ANDROGEN FOR SOCKEYE SALMON. Canadian Journal of Biochemistry and Physiology, 39(11), 1737-1742.

Jensen, K.M., Kahl, M.D., Makynen, E.A., Korte, J.J., Leino, R.L., Butterworth, B.C., & Ankley, G.T. (2004). Characterization of responses to the antiandrogen flutamide in a short-term reproduction assay with the fathead minnow. Aquatic Toxicology, 70(2), 99-110.

Jørgensen, A., Andersen, O., Bjerregaard, P., & Rasmussen, L.J. (2007). Identification and characterization of an androgen receptor from zebrafish Danio rerio. Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, 146(4), 561-568.

Kobayashi, Y., Nozu, R., & Nakamura, M. (2011). Role of estrogen in spermatogenesis in initial phase males of the three-spot wrasse (Halichoeres trimaculatus): effect of aromatase inhibitor on the testis. Developmental Dynamics, 240(1), 116-121.

Li, G.L., Liu, X.C., & Lin, H.R. (2007). Seasonal changes of serum sex steroids concentration and aromatase activity of gonad and brain in red-spotted grouper (Epinephelus akaara). Animal Reproduction Science, 99(1-2), 156-166.

Li, M., Liu, X., Dai, S., Xiao, H., Qi, S., Li, Y., Zheng, Q., Jie, M., Cheng, C.H.K., & Wang, D. (2020). Regulation of spermatogenesis and reproductive capacity by Igf3 in tilapia. Cellular and Molecular Life Sciences, 77(23), 4921-4938.

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