The Kiss1 gene encodes a family of neuropeptides named kisspeptins, which bind to a (former orphan) G-protein-coupled receptor called GPR54. Recent investigations suggest that kisspeptins play a vital role in regulating the secretion of gonadotropin-releasing hormone (GnRH). New evidence confirms that kisspeptins act through GPR54 to stimulate GnRH secretion. Kisspeptins and GPR54 are crucial for pubertal maturation in the primate. Kiss1 mRNA is differentially regulated by sex steroids in distinct hypothalamic nuclei.