animal
Farrin Babaei-Balderlou; Homayoun Khazali
Abstract
Introduction: It is well established that ghrelinerghic system has an inhibitory effect on reproductive activity. RFamide-related peptide-3 (RFRP-3) is one of the most important neuropeptides that regulates the mammalian reproduction. Studies have indicated the presence of the ghrelin receptor, called ...
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Introduction: It is well established that ghrelinerghic system has an inhibitory effect on reproductive activity. RFamide-related peptide-3 (RFRP-3) is one of the most important neuropeptides that regulates the mammalian reproduction. Studies have indicated the presence of the ghrelin receptor, called the growth hormone secretagogue receptor (GHS-R1a), in the RFRP-3 containing areas in the brain. Thus, it may be possible that ghrelinergic system involves in the control of reproduction through the RFRP-3. The aim of this study was to investigate the possible role of the GHS-R1a receptors in the regulation of RFRP-3 and its receptor GPR147 mRNA expression in the hypothalamus of male rats. Methods: 40 male Wistar rats in were divided in 8 groups (n=5) and each group received saline, 2,-4 or-8nmol ghrelin, 5,-10 or-20nmol D-Lys3-GHRP-6 (DLS), or concomitantly of ghrelin (4nmol) and DLS (10nmol) via the stereotaxically implanted cannula. Hypothalamus of rats was dissected 2h after treatment for evaluation of RFRP-3 and GPR147 mRNA levels. Results: Our findings indicated that 4nmol (P<0.05) or 8nmol (P<0.01) ghrelin injection significantly increased the RFRP-3 mRNA expression compare to saline group. While, the injection of 20nmol DLS significantly (P<0.05) decreased the RFRP-3-mRNA level when compared to saline group. Pretreatment of ghrelin-received animals with DLS prevented the increasing effects of ghrelin on RFRP-3 gene expression. Ghrelin or DLS had no significant effects on hypothalamic GPR147-mRNA levels. Conclusion: The acute activation of GHS-R1a by gherlin has a stimulatory role in hypothalamic RFRP-3 gene expression without any significant effects on GPR147-mRNA level in an acute treatment.
