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 ametastasis suppressor in human melanoma and breast cancer, is now recognized as themajor puberty gatekeeper and gonadotropin-releasing hormone (GnRH) neuroendocrinesystem modulator. It is a member of the family of RFamide-related peptides thatalso includes the neuropeptide FF group, the gonadotropin-inhibitory hormone, theprolactin-releasing peptide, and the 26RFa peptides. The KISS1 precursor peptide isprocessed into a family of peptides known as kisspeptins. Its expression has beendescribed in the hypothalamus as well as in the whole reproductive axis and severalextra 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 thekisspeptin system and its relation with reproduction in wild and non-classical laboratoryspecies is extremely useful to understand and become aware of the role of KISS1 in thewide variety of possible different reproductive strategies. In this chapter, KISS1 involvementin non-classical laboratory rodents, fishes, and birds is discussed.