Kisspeptin-10 is a natural brain peptide that talks to the GPR54 receptor to control the release of reproductive hormones. When you give kisspeptin, it directly stimulates the cells that make GnRH, which then boosts LH and FSH. Sex hormones like estrogen and testosterone feed back to kisspeptin‑producing neurons, turning them off in some brain areas and on in others, helping fine‑tune fertility cycles and hormone levels.

The Kiss1 gene codes for a family of peptides that act as endogenous ligands for the G protein-coupled receptor GPR54. Spontaneous mutations or targeted deletions of GPR54 in man and mice produce hypogonadotropic hypogonadism and infertility. Centrally administered kisspeptins stimulate gonadotropin secretion by acting directly on GnRH neurons. Sex steroids regulate the expression of KiSS-1 mRNA in the brain through direct action on KiSS-1 neurons. In the arcuate nucleus (Arc), sex steroids inhibit the expression of KiSS-1, suggesting that these neurons serve as a conduit for the negative feedback regulation of gonadotropin secretion. In the anteroventral periventricular nucleus (AVPV), sex steroids induce the expression of KiSS-1, implying that KiSS-1 neurons in this region may have a role in the preovulatory LH surge (in the female) or sexual behavior (in the male).