Kisspeptin has an independent and direct effect on the pituitary gland in the mare.
Abstract: To more clearly understand the equine gonadotrope response to kisspeptin and gonadotropin releasing hormone (GnRH), peripheral LH and FSH were quantified in diestrous mares after treatment with either equine kisspeptide (eKp-10, 0.5 mg iv), GnRH (25 μg iv), or a combination thereof every 4 h for 3 days. The following observations were made: 1) a diminished LH and FSH response to eKp-10 and GnRH was observed by Day 3, but was not different by treatment, 2) a decrease in basal LH concentration was observed from Day 1 to Day 3 for the eKp-10, but not the GnRH treated mares, 3) there was no change in basal FSH with either treatment. Additionally, pre-treatment with GnRH antagonist (antide 1.0 mg iv) eliminated any measurable change in LH after eKp-10 (1.0 mg iv) treatment. Both GnRH and kisspeptin are Gα coupled receptors, therefore quantifying the rise in intracellular calcium following treatment with cognate ligand allows simultaneous assessment of receptor activation. Direct stimulation of equine primary pituitary cells with GnRH and/or eKp-10 demonstrates three distinct populations of pituitary cells: one population responded to both eKp-10 and GnRH, a second, independent population, responded to only eKp-10, and a third population responded only to GnRH. These populations were confirmed using co-immunofluorescence of hemipituitaries from mares in diestrus. Although the rise in peripheral LH concentration elicited by eKp-10 is dependent on GnRH, this work suggests that kisspeptin also has a specific and direct effect on the equine gonadotrope, independent of GnRH.
Copyright © 2020. Published by Elsevier Inc.
Publication Date: 2020-07-29 PubMed ID: 32814247DOI: 10.1016/j.theriogenology.2020.07.031Google Scholar: Lookup
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- Journal Article
Summary
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This study examined the response of the equine pituitary gland to the hormones kisspeptin and gonadotropin-releasing hormone. It found that kisspeptin has a direct and independent effect on the pituitary gland of mares, apart from its interaction with gonadotropin-releasing hormone.
Study Overview
- The research focused on the response of the gonadotrope cells in the pituitary gland of female horses (mares) to the hormones kisspeptin and gonadotropin-releasing hormone (GnRH).
- A gonadotrope is a cell in the anterior pituitary gland that produces the hormones luteinizing hormone (LH) and follicle-stimulating hormone (FSH), crucial for reproduction.
- The hormones examined, kisspeptin and GnRH, play crucial roles in the regulation of the reproductive system.
Experimental Method
- The experiment involved treatment of the mares with kisspeptin or GnRH or a combination of both every 4 hours for a span of 3 days.
- LH and FSH levels were then measured in these horses after the treatment regimen.
- To identify the response of pituitary cells to the hormones, direct stimulation of primary pituitary cells with GnRH and/or kisspeptin was performed. The rise in intracellular calcium following treatment was then measured to assess receptor activation.
Key Findings
- The study found that there are three populations of pituitary cells in response to hormone treatment: one that responds to both kisspeptin and GnRH, one that responds only to kisspeptin, and one that responds only to GnRH.
- It was observed that a decrease in LH response to kisspeptin and GnRH was observed by Day 3.
- A decrease in basal LH concentration was noted for mares treated with kisspeptin, but not for those treated with GnRH.
- The research indicates that GnRH antagonist treatment eliminates any measurable change in LH following kisspeptin treatment.
Conclusions
- Although the rise in peripheral LH concentration elicited by kisspeptin is dependent on GnRH, this work suggests that kisspeptin has its independent role apart from GnRH on the gonadotropes in the pituitary gland of mares.
- This independent role of kisspeptin on pituitary cells can potentially pave the way for more thorough understanding of the hormonal control of reproduction in horses.
Cite This Article
APA
Magee C, Bruemmer JE, Kirkley KS, Sylvester LA, Runyan B, Nett TM, Squires EL, Clay CM.
(2020).
Kisspeptin has an independent and direct effect on the pituitary gland in the mare.
Theriogenology, 157, 199-209.
https://doi.org/10.1016/j.theriogenology.2020.07.031 Publication
Researcher Affiliations
- Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, CO, USA; Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA. Electronic address: Christianne.Magee@colostate.edu.
- Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, CO, USA; Department of Animal Sciences, College of Agricultural Sciences, Colorado State University, Fort Collins, CO, USA. Electronic address: jason.bruemmer@colostate.edu.
- Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, CO, USA; Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA. Electronic address: kelly.kirkley@colostate.edu.
- Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, CO, USA; Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA. Electronic address: luke.sylvester@rams.colostate.edu.
- Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, CO, USA; Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA. Electronic address: brittany.runyan@colostate.edu.
- Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, CO, USA; Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA. Electronic address: terry.nett@colostate.edu.
- Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, CO, USA. Electronic address: edward.squires@uky.edu.
- Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, CO, USA; Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA. Electronic address: colin.clay@colostate.edu.
MeSH Terms
- Animals
- Female
- Follicle Stimulating Hormone
- Gonadotropin-Releasing Hormone / metabolism
- Horses
- Kisspeptins / physiology
- Luteinizing Hormone
- Pituitary Gland / metabolism
Citations
This article has been cited 3 times.- Leonardi CEP, Carrasco RA, Dias FCF, Zwiefelhofer EM, Adams GP, Singh J. Mechanism of LH release after peripheral administration of kisspeptin in cattle. PLoS One 2022;17(12):e0278564.
- Okada CTC, Kaps M, Perez Quesada J, Gautier C, Aurich J, Aurich C. Diestrous Ovulations in Pregnant Mares as a Response to Low Early Postovulatory Progestogen Concentration. Animals (Basel) 2020 Nov 30;10(12).
- Akhtar MF, Ali S, Hassan F, Changfa W. Molecular pathways affecting reproductive efficiency in seasonal breeders: prospects and implications for improving fertility in donkeys. Front Vet Sci 2025;12:1633945.
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