Physiology of Gnrh and Gonadotropin Secretion

Abstract

Gonadotropin hormone-releasing hormone (GnRH) is the key regulator of the reproductive axis. Its pulsatile secretion determines the pattern of secretion of the gonadotropins follicle stimulating hormone and luteinising hormone, which then regulate both the endocrine function and gamete maturation in the gonads. Recent years have seen rapid developments in how GnRH secretion is regulated, with the discovery of the kisspeptin-neurokinin-dynorphin neuronal network in the hypothalamus. This mediates both positive and negative sex steroid feedback control of GnRH secretion, in conjunction with other neuropeptides and neurotransmitters. This review describes the main features of this regulatory system, including how its anatomical arrangements interact with functional control, and describes key differences between rodent and larger mammalian systems. For complete coverage of all related areas of Endocrinology, please visit our on-line FREE web-text, WWW.ENDOTEXT.ORG.