Active immunization of intact mares against gonadotropin-releasing hormone: differential effects on secretion of luteinizing hormone and follicle-stimulating hormone.
Abstract: Five lighthorse mares were actively immunized against gonadotropin releasing hormone (GnRH) to determine the relative importance of this hypothalamic hormone in the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Five mares immunized against the conjugation protein served as controls. Mares were initially immunized in November and received secondary immunizations 4 wk later, and then at 6-wk intervals until ovariectomy in June. All mares immunized against GnRH exhibited an increase (p less than 0.01) in the binding of tritiated GnRH by plasma, an indication that antibodies against this hormone had been elicited. Concentrations of LH, FSH and progesterone in weekly blood samples were lower (p less than 0.05) in GnRH-immunized mares than in controls after approximately 4 mo of immunization. However, the LH concentrations were affected to a greater degree than were FSH concentrations. All five control mares exhibited normal cycles of estrus and diestrus in spring, whereas no GnRH-immunized mare exhibited cyclic displays of estrus up to ovariectomy. All mares were injected intravenously with a GnRH analog (which cross-reacted less than 0.1% with the anti-GnRH antibodies) in May, after all control mares had displayed normal estrous cycles, to characterize the response of LH and FSH in these mares; two days later, the mares were injected with GnRH. The LH response to the analog, which was assessed by net area under the curve, was lower (p less than 0.01) by approximately 99% in mares immunized against GnRH than in control mares. In contrast, the FSH response to the analog was similar for both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1986-09-01 PubMed ID: 3094596DOI: 10.1095/biolreprod35.2.347Google Scholar: Lookup
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- Journal Article
Summary
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The research paper explores the varying effects of immunization against a specific hormone in horses on two different reproductive hormones. It demonstrates that luteinizing hormone secretion was more affected than follicle-stimulating hormone secretion.
Objective of the Research
- The aim of the research was to determine the importance of gonadotropin releasing hormone (GnRH), a hypothalamic hormone, in the secretion of two other hormones: luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
Methodology of the Research
- The researchers selected five lighthorse mares for this study. They were immunized against GnRH, and their reaction towards the different hormones was subsequently observed.
- Five other control mares were immunized against a different substance – the conjugation protein.
- The selected mares first received immunizations in November, followed by secondary immunizations 4 weeks later and then every 6 weeks until June.
- The response to the immunization was tracked by monitoring the level of tritiated GnRH binding, LH, FSH, and progesterone concentrations in the blood samples.
Findings of the Research
- It was observed that mares immunized against GnRH demonstrated an increased level of tritiated GnRH binding, which indicated that antibodies against this hormone were successfully developed.
- LH, FSH, and progesterone concentrations in blood samples of the mares immunized against GnRH were noticeably lower compared to the control group after approximately four months of immunization.
- LH concentrations were affected to a greater extent compared to the influence on FSH concentrations.
- Control mares exhibited regular estrus and diestrus cycles, whereas the mares immunized against GnRH did not demonstrate any cyclical estrus until ovariectomy was performed.
- Finally, when a GnRH analog was injected into the mares, it was found that the LH response in the GnRH-immunized mares was substantially lower, practically by about 99%. On the other hand, the FSH response was roughly similar in both groups.
Implications of the Research
- The results suggest a significant role of GnRH in the secretion of LH and FSH, especially the former. This understanding can greatly impact the understanding of reproductive health and cycles in mares and pave the way for further research in this field.
- The research highlights the significant potential of GnRH immunization in controlling reproductive function in mares, but it also raises questions about its potential side effects, emphasizing the need for a thorough follow-up study.
Cite This Article
APA
Garza F, Thompson DL, French DD, Wiest JJ, St George RL, Ashley KB, Jones LS, Mitchell PS, McNeill DR.
(1986).
Active immunization of intact mares against gonadotropin-releasing hormone: differential effects on secretion of luteinizing hormone and follicle-stimulating hormone.
Biol Reprod, 35(2), 347-352.
https://doi.org/10.1095/biolreprod35.2.347 Publication
Researcher Affiliations
MeSH Terms
- Anestrus
- Animals
- Biological Availability
- Female
- Follicle Stimulating Hormone / metabolism
- Horses
- Immunization
- Luteinizing Hormone / metabolism
- Ovariectomy
- Ovary / anatomy & histology
- Ovary / physiology
- Pituitary Gland / physiology
- Pituitary Hormone-Releasing Hormones / antagonists & inhibitors
- Pituitary Hormone-Releasing Hormones / immunology
- Pituitary Hormone-Releasing Hormones / physiology
Citations
This article has been cited 4 times.- Straticò P, Hattab J, Guerri G, Carluccio A, Bandera L, Celani G, Marruchella G, Varasano V, Petrizzi L. Behavioral Disorders in Mares with Ovarian Disorders, Outcome after Laparoscopic Ovariectomy: A Case Series. Vet Sci 2023 Jul 25;10(8).
- Aurich C, Kaps M. Suppression of reproductive behaviour and gonadal function in female horses-An update. Reprod Domest Anim 2022 Sep;57 Suppl 4(Suppl 4):4-12.
- Schwarzenberger F, Krawinkel P, Jeserschek SM, Schauerte N, Geiger C, Balfanz F, Knauf-Witzens T, Sicks F, Martinez Nevado E, Anfray G, Hein A, Kaandorp-Huber C, Marcordes S, Venshøj B. Immunocontraception of male and female giraffes using the GnRH vaccine Improvac®. Zoo Biol 2022 Jan;41(1):50-64.
- Baker DL, Powers JG, Ransom JI, McCann BE, Oehler MW, Bruemmer JE, Galloway NL, Eckery DC, Nett TM. Reimmunization increases contraceptive effectiveness of gonadotropin-releasing hormone vaccine (GonaCon-Equine) in free-ranging horses (Equus caballus): Limitations and side effects. PLoS One 2018;13(7):e0201570.
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