Effects of gonadotrophin-releasing hormone and prostaglandin F-2 alpha on corpus luteum function and timing of the subsequent ovulation in the mare.
Abstract: Standard bred mares that were cycling normally were treated beginning on Days 9 or 10 of the oestrous cycle with repeated pulses of GnRH (20 micrograms/h) and/or a single injection of prostaglandin (PG)F-2 alpha (alfaprostol, 3 mg), and were subsequently bled and palpated daily until the next ovulation. GnRH treatment increased serum concentrations of LH and progesterone at 4 days after the start of treatment compared to controls. The combination of PGF-2 alpha + GnRH treatment resulted in an immediate decline in serum progesterone values, and subsequently decreased the interval to next ovulation by 4.5 days compared to controls. Mean serum concentrations of FSH were not different among treatment groups 4 days after the start of treatment, and there was a consistent trend among all treatment groups for decreasing concentrations of FSH within the 6 days before ovulation. We conclude that, under our experimental conditions, pulsatile administration of GnRH provides a short-term luteotrophic stimulus, probably by the elevation in serum LH, but that this stimulus cannot indefinitely prevent the luteolytic effects of exogenously administered PGF-2 alpha. Although GnRH treatment combined with PGF-2 alpha injection hastened the impending ovulation, this regimen was no more effective than PGF-2 alpha treatment alone.
Publication Date: 1988-07-01 PubMed ID: 3137339DOI: 10.1530/jrf.0.0830545Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research investigates the influence of gonadotrophin-releasing hormone and prostaglandin F-2 alpha on the function of the corpus luteum and timing of subsequent ovulation in standard-bred mares. The study finds that the combined treatment of both hormones hastens the ovulation process but is not more effective than the use of prostaglandin F-2 alpha alone.
Methods and Treatments
- The experiment involved standard bred mares that were in the normal cycle.
- These mares received treatments starting from day 9 or 10 of the oestrous cycle.
- They were treated with repeated pulses of GnRH (20 micrograms/h) and/or a single injection of prostaglandin (PG)F-2 alpha (alfaprostol, 3 mg).
- After these treatments, they were bled and palpated daily until the next ovulation occurred.
Findings and Observations
- The GnRH treatment increased the serum concentrations of both LH and progesterone at 4 days after the treatment started compared to controls.
- When PGF-2 alpha and GnRH treatments were combined, it resulted in an immediate decline in serum progesterone values.
- This combination also decreased the interval to next ovulation by 4.5 days compared to controls.
- There was no significant difference in mean serum concentration of FSH among treatment groups 4 days after the treatment started.
- There was a consistent trend of decreasing concentrations of FSH within the 6 days before ovulation across all treatment groups.
Conclusion from the Research
- The pulsatile administration of GnRH provides a short-term stimulus to the luteotrophic process, likely due to the increase in serum LH.
- This stimulus, however, cannot indefinitely prevent the luteolytic effects of externally administered PGF-2 alpha.
- The combined treatment of GnRH and PGF-2 alpha hastens impending ovulation.
- However, the combination treatment does not prove to be more effective than the treatment of PGF-2 alpha alone.
Cite This Article
APA
Johnson AL, Becker SE, Roma ML.
(1988).
Effects of gonadotrophin-releasing hormone and prostaglandin F-2 alpha on corpus luteum function and timing of the subsequent ovulation in the mare.
J Reprod Fertil, 83(2), 545-551.
https://doi.org/10.1530/jrf.0.0830545 Publication
Researcher Affiliations
- Department of Animal Sciences, Rutgers, State University, New Brunswick, NJ 08903.
MeSH Terms
- Animals
- Corpus Luteum / drug effects
- Dinoprost
- Female
- Follicle Stimulating Hormone / blood
- Horses / physiology
- Luteinizing Hormone / blood
- Ovulation / drug effects
- Pituitary Hormone-Releasing Hormones / pharmacology
- Progesterone / blood
- Prostaglandins F / pharmacology
Citations
This article has been cited 1 times.- Kino S, Osawa T, Mizuno S, Watanabe G, Taya K, Izaike Y. Effect of Postbreeding Intramuscular Administration of Deslorelin Acetate on Plasma LH and Progesterone Concentrations and Conception Rate in Mares.. J Equine Sci 2014;25(1):23-7.
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