Novel insights into the metabolic action of Kiss1 neurons

Kiss1 neurons are essential regulators of the hypothalamic–pituitary–gonadal (HPG) axis by regulating gonadotropin-releasing hormone (GnRH) release. Compelling evidence suggests that Kiss1 neurons of the arcuate nucleus (Kiss1(ARC)), recently identified as the hypothalamic GnRH pulse generator driving fertility, also participate in the regulation of metabolism through kisspeptinergic and glutamatergic interactions with, at least, proopiomelanocortin (POMC) and agouti-related peptide (AgRP)/neuropeptide Y (NPY) neurons, located in close apposition with Kiss1(ARC). This review offers a comprehensive overview of the recent developments, mainly derived from animal models, on the role of Kiss1 neurons in the regulation of energy balance, including food intake, energy expenditure and the influence of circadian rhythms on this role. Furthermore, the possible neuroendocrine pathways underlying this effect, and the existing controversies related to the anorexigenic action of kisspeptin in the different experimental models, are also discussed.