Pulsatile secretion of gonadotrophic releasing hormone (GnRH) stimulates the anterior pituitary to release the gonadotrophic hormones, luteinizing hormone (LH), and follicle-stimulating hormone (FSH). These act on the gonads to promote gamete formation and the production of gonadal steroid hormones, which form feedback loops to regulate GnRH, LH, and FSH release.
Kisspeptin (Kiss1) neurons act as a principal relay for steroid feedback on GnRH secretion. In females, high levels of estrogens and progesterone stimulate kisspeptin neurons of the AVPV to induce the preovulatory surge of GnRH/LH, whereas they inhibit KISS1 expression in the arcuate nucleus (ARC). In the male, GnRH and gonadotrophic hormone release are negatively regulated by circulating testosterone, partly through the activity of kisspeptin neurons of the ARC.
POA, preoptic area; AVPV, anteroventral periventricular nucleus; ME, median eminence.