title: Comparative insights of the kisspeptin/kisspeptin receptor system: lessons from non-mammalian vertebrates.
abstract: Kisspeptins, the peptide products of the Kiss1 gene, were initially identified in mammals as ligands of the G protein-coupled receptor 54 (GPR54; also termed Kiss1R) with ability to suppress tumor metastasis. In late 2003, the indispensable role of kisspeptins in the control of reproductive function was disclosed by the seminal observations that humans and mice carrying inactivating mutations of GPR54 displayed hypogonadotropic hypogonadism. Since then, numerous experimental studies, conducted initially in several mammalian species, have substantiated the roles of kisspeptins as essential players in the physiologic regulation of key aspects of reproductive maturation and function, including the timing of puberty onset, the dynamic control of gonadotropin secretion via stimulation of GnRH neurons, the transmission of the negative and positive feedback effects of sex steroids, the metabolic regulation of fertility and the control of reproductive function by environmental (photoperiodic) cues. Notably, while studies about kisspeptins in non-mammals appeared initially to lag behind, significant efforts have been devoted recently to define the genomic organization and functional characteristics of kiss/kisspeptins and gpr54 in different non-mammalian species, including fish, reptiles and amphibians. These analyses, which will be comprehensively revised herein, have not only substantiated the conserved, essential roles of kisspeptins in the control of reproduction, but have also disclosed intriguing evolutionary aspects of kisspeptins and their receptors. Such comparative approaches will be instrumental to fuel further studies on the molecular regulation and physiological roles of kisspeptins, thus helping to unveil the complex biology of this system as indispensable regulator of the reproductive axis in a wide diversity of animal species.
authors.affiliation: Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Instituto Maimonides de Investigaciones Biomédicas de Córdoba and CIBER Fisiopatología de la Obesidad y Nutrición, 14004 Córdoba, Spain. fi1tesem@uco.es
authors.forename: Manuel
authors.initials: M
authors.lastname: Tena-Sempere
authors.forename: Alicia
authors.initials: A
authors.lastname: Felip
authors.forename: Ana
authors.initials: A
authors.lastname: Gómez
authors.forename: Silvia
authors.initials: S
authors.lastname: Zanuy
authors.forename: Manuel
authors.initials: M
authors.lastname: Carrillo
mesh_terms: D000663:Amphibians / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D005399:Fishes / Q000235:genetics / Q000378:metabolism*; D012739:Gonadal Steroid Hormones / Q000502:physiology; D059648:Kisspeptins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D017440:Photoperiod; D010802:Phylogeny; D012741:Sexual Maturation; D015398:Signal Transduction
chemical_list: D012739:Gonadal Steroid Hormones; D059648:Kisspeptins