Puberty is the transition from being sexually immature to sexual maturity and attainment of reproductive capacity. Complex interactions of hypothalamic-pituitary hormones and neuroendocrine factors take place to initiate puberty. Recent research indicates kisspeptin and its receptor GPR54 to play a key part in the initiation of puberty. Kisspeptin and GPR54 increase at the onset of puberty. Kisspeptin neurons innervate and stimulate hypothalamic gonadotropin releasing hormone (GNRH) neurons. In addition, kisspeptin neurons express estrogen and androgen receptors which may be important for the onset and tempo of puberty. The onset of puberty is also marked by increasing pulse and frequency of GNRH from the hypothalamus. GNRH then stimulates the pituitary to secrete gonadotropins (luteinizing hormone (LH) and follicle stimulating hormone (FSH)) which directly stimulates the ovaries or testes to produce sex steroids. The increase of sex...