Reproduction Abstracts

Kisspeptin-GPR54 signaling plays a key role to govern reproductive function through regulating GnRH/gonadotropin release in mammals, including rodents, ruminants, reflex ovulators, and primates. Surge and pulse modes of GnRH/gonadotropin secretion are responsible for ovulation and gametogenesis/steroidogenesis, respectively. It has been suggested that kisspeptin neurons located in the anterior hypothalamus, such as the anteroventral periventricular nucleus (AVPV) and preoptic area (POA), are responsible for the estrogen-positive feedback action to induce GnRH/gonadotropin surge and then ovulation. On the other hand, kisspeptin neurons in the arcuate nucleus (ARC) are considered to be involved in regulation of GnRH/gonadotropin pulses and estrogen negative feedback. The present paper reviews the role of two populations of kisspeptin neurons with a focus on the epigenetic mechanism mediating the estrogen action on Kiss1 gene expression in the brain to understand the mechanism underlying regulation of GnRH/gonadotropin release by kisspeptin. This work was supported in part by the Research Program on Innovative Technologies for Animal Breeding, Reproduction, and Vaccine Development.