Hypothalamic distribution, adenohypophyseal receptor expression, and ligand functionality of RFamide-related peptide 3 in the mare during the breeding and nonbreeding seasons.
Abstract: RFamide-related peptide 3 (RFRP3), the mammalian homologue of avian gonadotropin-inhibitory hormone, has been shown to negatively regulate the secretion of LH and may contribute to reproductive seasonality in some species. Herein, we examined the presence and potential role of the RFRP3-signaling system in regulating LH secretion in the mare during the breeding and nonbreeding seasons. Hypothalamic NPVF mRNA (the precursor mRNA for RFRP3) was detected at the level of the dorsomedial nucleus and paraventricular nucleus, but expression did not change with season. A greater number of RFRP3-expressing cells was observed throughout the rostral-caudal extension of the dorsomedial nucleus. Furthermore, adenohypophyseal expression of the RFRP3 receptor (NPFFR1) during the winter anovulatory season did not differ from that during either the follicular or luteal phases of the estrous cycle. When tested in primary adenohypophyseal cell culture or in vivo during both the breeding and nonbreeding seasons, neither equine nor ovine peptide sequences for RFRP3 suppressed basal or GnRH-mediated release of LH. However, infusion of RF9, an RFRP3 receptor-signaling antagonist, into seasonally anovulatory mares induced a robust increase in secretion of LH both before and following continuous treatment with GnRH. The results indicate that the cellular machinery associated with RFRP3 function is present in the equine hypothalamus and adenohypophysis. However, evidence for functionality of the RFRP3-signaling network was only obvious when an antagonist RF9 was employed. Because GnRH-induced release of LH was not affected by RF9, its actions may occur upstream from the gonadotrope to stimulate or disinhibit secretion of GnRH.
Publication Date: 2014-02-13 PubMed ID: 24389874DOI: 10.1095/biolreprod.113.112185Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research article focuses on the role of RFamide-related peptide 3 (RFRP3), a hormone known to regulate reproduction in some species, in horses during different reproductive seasons. The study found that, while the systems for RFRP3 function are present in horses, its effects are mostly visible when its antagonist, the RF9 molecule, is used, suggesting RF9 may play a key role in stimulating or increasing secretion of the Gonadotropin-Releasing Hormone (GnRH).
Overview of the Research Objectives and Approach
- This study aimed to understand the presence and role of RFamide-related peptide 3 (RFRP3) in horses during different reproductive phases, specifically the breeding and nonbreeding seasons.
- The researchers also explored whether alterations in the RF9 molecule, an antagonist of the RFRP3 hormone, could influence the secretion of the Gonadotropin-Releasing Hormone (GnRH).
Key Findings of the Research
- The presence of RFRP3 was confirmed in the hypothalamus and adenohypophysis of horses. However, its expression did not vary between the breeding and nonbreeding seasons.
- A greater number of RFRP3-expressing cells were observed in the dorsomedial nucleus, a region in the hypothalamus.
- The adenohypophyseal expression of NPFFR1, the receptor for RFRP3, didn’t vary significantly between different reproductive phases.
- Neither equine nor ovine peptide sequences for RFRP3 suppressed the release of LH, a reproductive hormone. However, infusion of RF9 caused a significant increase in LH secretion.
- Importantly, the RF9 induced increase in LH was not affected by the GnRH, suggesting that RF9 may act on processes upstream of the GnRH.
Conclusion and Implications
- The findings suggest that while RFRP3 exists in the hypothalamus and adenohypophysis of horses and its mechanisms are functional, its influence on LH secretion and thus on reproduction is not direct but mediated via the RF9 molecule.
- RF9, by acting on processes that may stimulate or increase secretion of GnRH, can potentially impact the reproductive processes in horses. This discovery may open new ways to manage reproductive cycles and fertility in horses.
Cite This Article
APA
Thorson JF, Prezotto LD, Cardoso RC, Sharpton SM, Edwards JF, Welsh TH, Riggs PK, Caraty A, Amstalden M, Williams GL.
(2014).
Hypothalamic distribution, adenohypophyseal receptor expression, and ligand functionality of RFamide-related peptide 3 in the mare during the breeding and nonbreeding seasons.
Biol Reprod, 90(2), 28.
https://doi.org/10.1095/biolreprod.113.112185 Publication
Researcher Affiliations
- Animal Reproduction Laboratory, Texas A&M AgriLife Research, Beeville, Texas.
MeSH Terms
- Animals
- Breeding
- Cells, Cultured
- Female
- Horses / genetics
- Horses / metabolism
- Hypothalamus / drug effects
- Hypothalamus / metabolism
- Neuropeptides / genetics
- Neuropeptides / metabolism
- Neuropeptides / pharmacology
- Pituitary Gland, Anterior / drug effects
- Pituitary Gland, Anterior / metabolism
- Receptors, Neuropeptide / genetics
- Receptors, Neuropeptide / metabolism
- Reproduction / physiology
- Seasons
- Tissue Distribution
Citations
This article has been cited 8 times.- Bédécarrats GY, Hanlon C, Tsutsui K. Gonadotropin Inhibitory Hormone and Its Receptor: Potential Key to the Integration and Coordination of Metabolic Status and Reproduction. Front Endocrinol (Lausanne) 2021;12:781543.
- Zhao S, Guo Z, Xiang W, Wang P. The neuroendocrine pathways and mechanisms for the control of the reproduction in female pigs. Anim Reprod 2021;18(4):e20210063.
- Teo CH, Phon B, Parhar I. The Role of GnIH in Biological Rhythms and Social Behaviors. Front Endocrinol (Lausanne) 2021;12:728862.
- Mohapatra SS, Mukherjee J, Banerjee D, Das PK, Ghosh PR, Das K. RFamide peptides, the novel regulators of mammalian HPG axis: A review. Vet World 2021 Jul;14(7):1867-1873.
- Kriegsfeld LJ, Jennings KJ, Bentley GE, Tsutsui K. Gonadotrophin-inhibitory hormone and its mammalian orthologue RFamide-related peptide-3: Discovery and functional implications for reproduction and stress. J Neuroendocrinol 2018 Jul;30(7):e12597.
- Ubuka T, Parhar I. Dual Actions of Mammalian and Piscine Gonadotropin-Inhibitory Hormones, RFamide-Related Peptides and LPXRFamide Peptides, in the Hypothalamic-Pituitary-Gonadal Axis. Front Endocrinol (Lausanne) 2017;8:377.
- Osugi T, Ubuka T, Tsutsui K. Review: evolution of GnIH and related peptides structure and function in the chordates. Front Neurosci 2014;8:255.
- Wei J, Sun J, Pan Y, Cao M, Wang Y, Yuan T, Guo A, Han R, Ding X, Yang G, Yu T, Ding R. Revealing genes related teat number traits via genetic variation in Yorkshire pigs based on whole-genome sequencing. BMC Genomics 2024 Dec 18;25(1):1217.
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