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Event: 1695
Key Event Title
Impaired ovulation
Short name
Biological Context
Level of Biological Organization |
---|
Organ |
Organ term
Organ term |
---|
female gonad |
Key Event Components
Process | Object | Action |
---|---|---|
ovulation | Ovum | decreased |
Key Event Overview
AOPs Including This Key Event
AOP Name | Role of event in AOP | Point of Contact | Author Status | OECD Status |
---|---|---|---|---|
Luteinizing hormone receptor antagonism | KeyEvent | Young Jun Kim (send email) | Under Development: Contributions and Comments Welcome | |
Decreased GnRH release leading to increased E2 | KeyEvent | Martina Panzarea (send email) | Under development: Not open for comment. Do not cite |
Taxonomic Applicability
Term | Scientific Term | Evidence | Link |
---|---|---|---|
mammals | mammals | NCBI |
Life Stages
Life stage | Evidence |
---|---|
Adults |
Sex Applicability
Term | Evidence |
---|---|
Female |
Key Event Description
How It Is Measured or Detected
For rodent studies, a few methods of measurement of ovulation are available.
Vaginal cytology is a method to assess the stage in the estrous cycle. This is done by flushing the vagina or collecting a vaginal swab followed by staining to observe cytology and determine the stage.
Another determinant of ovulation is the presence of corpus lutea. After sacrifice of the female mouse or rat, sections of the reproductive organs are stained, and histological examination is performed to count and identify corpus luteum.
Finally, the most direct method is the flushing of the oviduct. Once the estrous stage is determined, female mice can be placed in presence of males to induce ovulation. This is determined the next morning due to the presence of a vaginal plug. The mice are then euthanized, and the oviducts are flushed. The number of ova (mature oocytes) are counted to determine the quality of ovulation. The number of females that have ova in the oviduct is an additional measurement that may be taken into account (Ajayi and Akhigbe, 2020; Byers et al., 2012; Caligioni, 2009).
Regarding in vitro studies, involving human or rat granulosa cells for example, ovulation is not measured the same way since it does not occur in these systems. However, mRNA expression and profiles of ovulation markers can be investigated. Certain genes are overexpressed during ovulation and are considered markers of ovulation, such as AREG and EREG, shown in many studies (Fa et al., 2013; Pogrmic-Majkic et al., 2018).
Domain of Applicability
While in many species, ovulation is dependent on LH surge, some species differences exist in regulation of this process. Ovulation is applicable to females starting from puberty and during adult life.
References
Ajayi AF and Akhigbe RE, 2020. Staging of the estrous cycle and induction of estrus in experimental rodents: an update. Fertil Res Pract, 6:5. doi: 10.1186/s40738-020-00074-3
Byers SL, Wiles MV, Dunn SL and Taft RA, 2012. Mouse estrous cycle identification tool and images. PLoS One, 7:e35538. doi: 10.1371/journal.pone.0035538
Caligioni CS, 2009. Assessing reproductive status/stages in mice. Curr Protoc Neurosci, Appendix 4:Appendix 4I. doi: 10.1002/0471142301.nsa04is48
Fa S, Pogrmic-Majkic K, Samardzija D, Glisic B, Kaisarevic S, Kovacevic R and Andric N, 2013. Involvement of ERK1/2 signaling pathway in atrazine action on FSH-stimulated LHR and CYP19A1 expression in rat granulosa cells. Toxicol Appl Pharmacol, 270:1-8. doi: 10.1016/j.taap.2013.03.031
Pogrmic-Majkic K, Samardzija D, Stojkov-Mimic N, Vukosavljevic J, Trninic-Pjevic A, Kopitovic V and Andric N, 2018. Atrazine suppresses FSH-induced steroidogenesis and LH-dependent expression of ovulatory genes through PDE-cAMP signaling pathway in human cumulus granulosa cells. Mol Cell Endocrinol, 461:79-88. doi: 10.1016/j.mce.2017.08.015