Concentrations of inhibin, progesterone and oestradiol in fluid from dominant and subordinate follicles from mares during spring transition and the breeding season.
Abstract: Dominant and subordinate follicles were collected from mares on the day after the dominant follicle reached 30 mm in diameter, to investigate regulation of folliculogenesis during spring transition and the breeding season. Concentrations of oestradiol-17beta, progesterone and inhibin A, but not inhibin isoforms with pro- and alpha C-immunoreactivity, were significantly higher in preovulatory follicles than in dominant anovulatory transitional follicles. Steroidogenic activity was regained gradually in the dominant follicles of successive anovulatory waves through spring transition. The dominant follicles, during both spring transition and cyclicity, contained higher concentrations of oestradiol, progesterone and inhibin A, but not inhibin pro- and alpha C-isoforms, than subordinate follicles. The results indicate that high follicular levels of oestradiol, progesterone and inhibin A are associated with continued follicle growth and ovulation. The low concentrations of oestradiol and progesterone in transitional follicles indicate that the deficiency in steroidogenesis exists early in the steroidogenic pathway. The similarity in patterns of follicular hormones in spring transition and during cyclicity strongly suggests that the mechanism of dominance is the same in both types of follicle.
Publication Date: 2002-10-16 PubMed ID: 12379375DOI: 10.1016/s0378-4320(02)00170-7Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study examines the concentrations of specific hormones in dominant and subordinate follicles in mares during the transition into spring and the breeding season. The research finds that the hormone levels influence continuous follicle growth and ovulation, with lower hormone levels indicating early deficiencies in production.
Objective of the Study
- Researchers aimed to explore the regulation of folliculogenesis during spring transition and the breeding season in mares. They did this by analyzing the concentrations of specific hormones in dominant and subordinate follicles when the dominant follicle reached 30 mm in diameter.
Key Findings of the Research
- The levels of oestradiol-17beta, progesterone, and inhibin A were found to be significantly higher in preovulatory follicles than in dominant anovulatory transitional follicles. However, inhibin isoforms with pro- and alpha C-immunoreactivity did not show any significant difference.
- Through the spring transition, the dominant follicles gradually regained their steroidogenic activity after successive anovulatory waves.
- The dominant follicles held greater concentrations of oestradiol, progesterone, and inhibin A during both the spring transition and the cyclicality phase as opposed to the subordinate follicles. No difference was observed in the levels of inhibin pro- and alpha C-isoforms between the two types of follicles.
Implications of the Findings
- High follicular levels of oestradiol, progesterone, and inhibin A were found to be associated with sustained follicle growth and ovulation, indicating the crucial role these hormones play.
- The lower concentrations of oestradiol and progesterone in transitional follicles indicated that a deficiency in steroidogenesis, or hormone production, was present early in the steroidogenic pathway.
- The observed similarity between the profiles of follicular hormone during spring transition and cyclicity implied that the dominance mechanism applies equally to both types of follicles.
Cite This Article
APA
Watson ED, Thomassen R, Steele M, Heald M, Leask R, Groome NP, Riley SC.
(2002).
Concentrations of inhibin, progesterone and oestradiol in fluid from dominant and subordinate follicles from mares during spring transition and the breeding season.
Anim Reprod Sci, 74(1-2), 55-67.
https://doi.org/10.1016/s0378-4320(02)00170-7 Publication
Researcher Affiliations
- Department of Veterinary Clinical Studies, University of Edinburgh, Easter Bush, EH25 9RG, Midlothian, UK. elaine.watson@ed.ac.uk
MeSH Terms
- Animals
- Estradiol / blood
- Estradiol / metabolism
- Female
- Follicle Stimulating Hormone / blood
- Follicle Stimulating Hormone / metabolism
- Follicular Fluid / chemistry
- Follicular Fluid / metabolism
- Horses / metabolism
- Horses / physiology
- Inhibins / blood
- Inhibins / metabolism
- Luteinizing Hormone / blood
- Luteinizing Hormone / metabolism
- Ovarian Follicle / metabolism
- Ovarian Follicle / physiology
- Progesterone / blood
- Progesterone / metabolism
- Seasons
Citations
This article has been cited 3 times.- Ishak GM, Bashir ST, Dutra GA, Gastal GDA, Gastal MO, Cavinder CA, Feugang JM, Gastal EL. In vivo antral follicle wall biopsy: a new research technique to study ovarian function at the cellular and molecular levels.. Reprod Biol Endocrinol 2018 Jul 28;16(1):71.
- Filannino A, Stout TA, Gadella BM, Sostaric E, Pizzi F, Colenbrander B, Dell'Aquila ME, Minervini F. Dose-response effects of estrogenic mycotoxins (zearalenone, alpha- and beta-zearalenol) on motility, hyperactivation and the acrosome reaction of stallion sperm.. Reprod Biol Endocrinol 2011 Oct 5;9:134.
- Medan MS, Nambo Y, Nagamine N, Shinbo H, Watanabe G, Groome N, Taya K. Plasma concentrations of ir-inhibin, inhibin A, inhibin pro-alphaC, FSH, and estradiol-17beta during estrous cycle in mares and their relationship with follicular growth.. Endocrine 2004 Oct;25(1):7-14.
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