[Melatonin regulates ovarian function: an update].

Melatonin (N-acetyl-5-methoxytryptamine, MT) is a hormone synthesized and secreted by the pineal gland. Recent studies show that melatonin plays an essential role in the pathogenesis of many reproductive processes. High-concentration melatonin exists in human preovulatory follicular fluid and melatonin receptors are present in ovarian granulosa cells, which indicates the direct effects of melatonin on ovarian function. Reactive oxygen species are involved in a number of reproductive events, including folliculogenesis, follicular atresia, ovulation, oocyte maturation, and corpus luteum formation. Melatonin and its metabolites, as powerful antioxidants and free radical scavengers, can potentially inhibit premature ovarian failure. Literature published in recent years shows the essential roles of melatonin in improving human ovarian function and oocyte quality as well as in the management of infertility. Researches on the action mechanisms of melatonin may provide a theoretical basis for the prevention and treatment of some clinical diseases.