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Ovulation is caused by a sequence of neuroendocrine events: GnRH and LH surges that are induced by positive feedback action of estrogen secreted by the mature ovarian follicles. The central mechanism of positive feedback action of estrogen on GnRH/LH secretion, however, is not fully understood yet. The present study examined whether metastin, the product of(More)
Metastin/kisspeptin, the KiSS-1 gene product, has been identified as an endogenous ligand of GPR54 that reportedly regulates GnRH/LH surges and estrous cyclicity in female rats. The aim of the present study was to determine if metastin/kisspeptin neurons are a target of estrogen positive feedback to induce GnRH/LH surges. We demonstrated that preoptic area(More)
Kisspeptin, a peptide encoded by the Kiss1 gene, has been considered as a potential candidate for a factor triggering the onset of puberty, and its expression in the hypothalamus was found to increase during peripubertal period in rodent models. The present study aimed to clarify the oestrogenic regulation of peripubertal changes in Kiss1 mRNA expression in(More)
The brain mechanism regulating gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) release is sexually differentiated in rodents. Kisspeptin neurons in the anteroventral periventricular nucleus (AVPV) have been suggested to be sexually dimorphic and involved in the GnRH/LH surge generation. The present study aimed to determine the significance of(More)
Follicular development and ovulation are suppressed during lactation in various mammalian species, mainly due to the suppression of pulsatile GnRH/LH secretion. Metastin (kisspeptin-54), a KiSS-1 gene product, is an endogenous ligand for GPR54, a G-protein-coupled receptor, and suggested to play a critical role in regulating the gonadal axis. The present(More)
Gonadotropin-releasing hormone (GnRH) secretion has two modes of release in mammalian species; the surge mode and the pulse mode. The surge mode, which is required for the induction of the preovulatory gonadotropin discharge in most species, is induced by the positive feedback of estrogen secreted by the mature ovarian follicle. The pulse mode of GnRH(More)
The present study was conducted to determine the morphological and functional interaction between kisspeptin and gonadotrophin-releasing hormone (GnRH) neuronal elements at the median eminence in female rats to clarify a possibility that kisspeptin directly stimulates GnRH release at the nerve end. A dual immunoelectron microscopic study of kisspeptin and(More)
Galanin-like peptide (GALP), a ligand for three types of galanin receptor, is reported to have a role in regulating luteinising hormone (LH) release in male rodents and primates, but its role in LH release in female rodents remains controversial. The present study was conducted to test whether GALP has a stimulatory role in regulating LH secretion in female(More)
The aim of this study was to identify the presence of functional oxytocin (OT) receptors on bovine granulosa cells. Freshly prepared bovine granulosa cells from small (3-5 mm in diameter) or preovulatory (mature) follicles were examined for OT receptors by a radioreceptor assay. Scatchard analysis revealed that both binding capacity and affinity in(More)
This study aims to determine the epigenetic mechanism regulating Kiss1 gene expression in the anteroventral periventricular nucleus (AVPV) to understand the mechanism underlying estrogen-positive feedback action on gonadotropin-releasing hormone/gonadotropin surge. We investigated estrogen regulation of the epigenetic status of the mouse AVPV Kiss1 gene(More)