Response of plasma LH and FSH to gonadotropin-releasing hormone in pony foals and ovariectomized pony mares.
Abstract: Plasma FSH and LH response to a synthetic GnRH analog was measured in adult ovariectomized pony mares (OVX) and in pony foals (<70 days of age) during late spring (May-June). FSH and LH responded in a similar fashion (200% increase) in the OVX mare, which is different from other reports for intact mares. There was a greater mean response to a comparable dose of GnRH in the prepubertal foal for both FSH (500%) and LH (900%) than in the OVX mare. There was a positive correlation between age and the maximum FSH response to GnRH in male and female foals. The LH response was positively correlated with age in male foals, but not in females. The response to GnRH in the prepubertal foals was consistent with the previously observed patterns of gonadotropin secretion during this age period.
Publication Date: 1980-08-01 PubMed ID: 16725517DOI: 10.1016/0093-691x(80)90098-9Google Scholar: Lookup
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- Journal Article
Summary
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This research looks at how levels of certain hormones in ponies – specifically follicle-stimulating hormone (FSH) and luteinizing hormone (LH) – respond to a treatment with a hormone analogue called GnRH. The study explored the responses in young ponies and in adult mares who have had their ovaries removed.
Study Participants and Methodology
- Two main groups were included in this study: adult pony mares that have had their ovaries removed (referred to as OVX) and young ponies, typically less than 70 days old.
- The response of hormones follicle-stimulating hormone (FSH) and luteinizing hormone (LH) to a synthetic hormone analog known as gonadotropin-releasing hormone (GnRH) was measured. This was conducted during late spring (May-June), a season known for certain hormonal changes in ponies.
Findings and Comparisons
- The study found the response of both FSH and LH to be the same in the OVX mares, which included a 200% increase in the hormone levels. This finding contrasted with prior studies in intact mares that indicated a different hormonal response.
- In the case of prepubertal foals, the responses to GnRH were significantly higher compared to the OVX mares. Specifically, FSH levels increased to 500% and LH levels to 900%.
Correlations with Age and Gender
- The research indicated a positive correlation between the age of the foals and the maximum FSH response, meaning as the foals got older, the FSH levels increased more in reaction to GnRH. This was seen in both male and female foals.
- For the LH hormone, a similar correlation was found but only in male foals. Female foals showed no such correlation between age and LH response.
Consistency with Past Observations
- The pattern of hormone responses observed in the prepubertal foals in this study matches with previously seen patterns of gonadotropin secretion during the same age period. This validity check not only adds credibility to this research but also furthers our understanding of gonadotropin secretion in prepubertal foals.
Cite This Article
APA
Wesson JA, Miller KF, Ginther OJ.
(1980).
Response of plasma LH and FSH to gonadotropin-releasing hormone in pony foals and ovariectomized pony mares.
Theriogenology, 14(2), 113-121.
https://doi.org/10.1016/0093-691x(80)90098-9 Publication
Researcher Affiliations
- Department of Veterinary Science, University of Wisconsin, Madison 53706, USA.
Citations
This article has been cited 2 times.- Tonai S, Kawabata A, Nakanishi T, Lee JY, Okamoto A, Shimada M, Yamashita Y. Iron deficiency induces female infertile in order to failure of follicular development in mice. J Reprod Dev 2020 Oct 13;66(5):475-483.
- Ishimaru M, Kume K, Murase H, Sato F, Matsui A, Ohmura H, Taya K. Effect of birth month on endocrine function in Thoroughbred foals born in Hokkaido, the northern part of Japan. J Vet Med Sci 2025 Jul 7;87(7):804-815.
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