Distribution of the kisspeptin system and its relation with gonadotropin-releasing hormone in the hypothalamus.

Abstract

Kisspeptin (KISS1), originally catalogued as metastin because of its capacity as a metastasis suppressor in human melanoma and breast cancer, is now recognized as the major puberty gatekeeper and gonadotropin-releasing hormone (GnRH) neuroendocrine system modulator. It is a member of the family of RFamide-related peptides that also includes the neuropeptide FF group, the gonadotropin-inhibitory hormone, the prolactin-releasing peptide, and the 26RFa peptides. The KISS1 precursor peptide is processed into a family of peptides known as kisspeptins. Its expression has been described in the hypothalamus as well as in the whole reproductive axis and several extra reproductive tissues of mammals as well as fish and amphibians, but not in birds. KISS1 plays an essential role as a regulator of the reproductive axis by inducing the synthesis and release of GnRH, acting through specific receptors. The study of the kisspeptin system and its relation with reproduction in wild and non-classical laboratory species is extremely useful to understand and become aware of the role of KISS1 in the wide variety of possible different reproductive strategies. In this chapter, KISS1 involvement in non-classical laboratory rodents, fishes, and birds is discussed.