Gonadotropin-inhibitory hormone (GnIH) was discovered as a novel hypothalamic peptide that inhibits gonadotropin release in the quail. The presence of GnIH-homologous peptides and its receptors (GnIHRs) have been demonstrated in various vertebrate species including teleosts, suggesting that the GnIH-GnIHR family is evolutionarily conserved. In avian and mammalian brain, GnIH neurons are localiz...

Since the discovery of gonadotropin-releasing hormone (GnRH) in mammals at the beginning of the 1970s, it was generally accepted that GnRH is the only hypothalamic neuropeptide regulating gonadotropin release in mammals and other vertebrates. In 2000, however, gonadotropin-inhibitory hormone (GnIH), a novel hypothalamic neuropeptide that actively inhibits gonadotropin release, was discovered in...

Seasonal reproduction in birds is the adaptation to breed at the time of the greatest survival of young. This exact moment is mainly imposed by the photoperiod which stimulates the hypothalamo-pituitary-gonadal axis and starts breeding season. This article summarizes present knowledge concerning: 1/ perception and transduction of light into the biological signal; 2/ model of the avian photoperi...

Introduction: Gonadotropin inhibitory hormone (GnIH) is believed to be an inhibitor of gonadotropin releasing hormone (GnRH) secretion. The role of GnIH in lactational inhibition of gonadotropin secretion is not well known therefore, the aim of the present study was to evaluate the effect of lactation on expression of GnIH in these nuclei of lactating and non-lactating rats. Methods: Ten po...

Follicular fluid obtained from medium or large bovine ovarian follicles inhibited ovarian luteinizing hormone/human chorionic gonadotropin sensitive adenylate cyclase in a dose-dependent manner (150'3 mg follicular fluid protein/ml). The inhibitory activity was excluded by Sephadex G-10 and was fully retained following treatment with charcoal. Fluoride-stimulated enzyme activity was not inhibit...

this study explored the effects of gnrh agonist (gnrha) immunity on expression of fshr mrna in pituitary and fshr protein in uteri, and also confirmed its efficacy on uterine development. 42 prepuberty and non cyclic ewes were assigned to 6 experimental groups (eg) during anestrus season. animals in eg-i, eg-ii and eg-iii were subcutaneously injected with 200, 300 and 400 μg alarelin antigens (...