Effects of age, season, and fertility status on plasma and intratesticular immunoreactive (IR) inhibin concentrations in stallions.
Abstract: The nature of the relationship between inhibin and reproductive function in the stallion is yet to be elucidated. Blood and testes from 51 light horse stallions ranging in age from 2 mo to 25 years were collected during the breeding and nonbreeding seasons to study the effects of testicular maturation, aging, season, and fertility status on peripheral and intratesticular concentrations of Ir inhibin and other reproductive hormones. Of the 51 stallions, 12 age-matched stallions (6 fertile, 3 subfertile, and 3 infertile) were used in the fertility study. Blood samples were taken before castration and plasma stored at -20 degrees C for analysis of Ir inhibin, luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T), estradiol (E2), and estrogen conjugates (EC) by radioimmunoassay (RIA). Testes were homogenized and testicular extracts prepared and frozen at -70 degrees C for analysis of Ir inhibin, T, E2, and EC by RIA. Plasma concentrations of Ir inhibin, LH, FSH, T, E2, and EC and intratesticular concentrations of Ir inhibin, T, E2, and EC increased with age (P < 0.01). The most dramatic effect appeared to be during testicular maturation. An aging effect was not observed in adult stallions. A seasonal effect was not detected for any of the plasma hormones, whereas for the intratesticular hormones the only change noted was an increase in T in the nonbreeding season (P < 0.05). Plasma Ir inhibin, E2, and EC were lower (P < 0.01) and gonadotropins higher (P < 0.05) in infertile stallions. Plasma T levels did not change. Intratesticular Ir inhibin concentrations tended to be lower (P < 0.1) in subfertile stallions and significantly lower (P < 0.01) in infertile stallions, whereas intratesticular steroid levels were not different among the three groups. In conclusion, plasma and intratesticular Ir inhibin concentrations seem to be affected by testicular maturation and fertility status.
Publication Date: 1998-04-09 PubMed ID: 9532426DOI: 10.1016/s0739-7240(97)00083-0Google Scholar: Lookup
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- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research paper examines the connection between an hormone known as inhibin and reproductive function in stallions. It studies the impact of various factors such as age, season, and fertility on levels of this hormone.
Research Methodology
- The research involves a study conducted on 51 light horse stallions ranging in age from 2 months to 25 years. The samples were taken during breeding and nonbreeding seasons.
- Out of these 51 stallions, 12 of them that were age-matched were utilized for a fertility study.
- These 12 were categorized according to their fertility status – 6 were fertile, 3 were subfertile and 3 infertile. This helped in understanding the effect of fertility on inhibin levels.
- Blood samples were collected before castration and testes samples were homogenized for analysis. These were stored at low temperatures for later analysis.
- The samples were analyzed for various types of hormones including inhibin, luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T), estradiol (E2), and estrogen conjugates (EC).
Research Findings
- The research found that plasma concentrations of inhibin, LH, FSH, T, E2, and EC and intratesticular concentrations of inhibin, T, E2, and EC increased with age.
- The evidence found points towards the fact that the most dramatic increase in these hormone levels was during testicular maturation.
- No significant difference was found in hormones level within adult stallions as they aged further. Therefore, age did not have a significant impact in adult stallions.
- No seasonal effect was found on any of the plasma hormones. However, increase in testosterone was observed in the nonbreeding season in the intratesticular hormones.
- The hormone levels in infertile stallions notably varied with lower plasma levels of inhibin, E2, and EC but higher levels of gonadotropins. There was no change in plasma testosterone levels.
- Intratesticular inhibin concentrations were found to be lower in subfertile and infertile stallions. However, intratesticular steroid levels remained the same among all three fertility groups.
Research Conclusion
- In conclusion, the hormone inhibin levels in the plasma and intratesticular samples was observed to be influenced by testicular maturation and a stallion’s fertility status.
Cite This Article
APA
Stewart BL, Roser JF.
(1998).
Effects of age, season, and fertility status on plasma and intratesticular immunoreactive (IR) inhibin concentrations in stallions.
Domest Anim Endocrinol, 15(2), 129-139.
https://doi.org/10.1016/s0739-7240(97)00083-0 Publication
Researcher Affiliations
- Department of Animal Science, University of California, Davis 95616, USA.
MeSH Terms
- Aging / blood
- Aging / metabolism
- Animals
- Cohort Studies
- Estradiol / analysis
- Estradiol / blood
- Estrogens, Conjugated (USP) / analysis
- Estrogens, Conjugated (USP) / blood
- Fertility / physiology
- Follicle Stimulating Hormone / blood
- Horses / blood
- Horses / metabolism
- Horses / physiology
- Hydrogen-Ion Concentration
- Inhibins / analysis
- Inhibins / blood
- Luteinizing Hormone / blood
- Male
- Seasons
- Semen / chemistry
- Semen / cytology
- Semen / physiology
- Sperm Motility / physiology
- Testis / chemistry
- Testis / growth & development
- Testosterone / analysis
- Testosterone / blood
Citations
This article has been cited 3 times.- Shakeel M, Yoon M. Functions of somatic cells for spermatogenesis in stallions. J Anim Sci Technol 2022 Jul;64(4):654-670.
- Toishi Y, Tsunoda N, Nagata SI, Kirisawa R, Nagaoka K, Watanabe G, Yanagawa Y, Katagiri S, Taya K. Evaluation of the chemiluminescent enzyme immunoassay system for the measurement of testosterone in the serum and whole blood of stallions. J Reprod Dev 2018 Feb 27;64(1):41-47.
- Ferrer MS, Lutjemeier BJ, Koopman T, Pierucci-Alves F, Weiss ML. Xenogeneic transplantation of equine testicular cells into seminiferous tubules of immunocompetent rats. Theriogenology 2011 Apr 15;75(7):1258-64.
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