Melatonin induces progesterone production in human granulosa-lutein cells through upregulation of StAR expression

fertilization (IVF). Using pharmacological inhibitors, we show that the stimulatory effect of melatonin on StAR expression is mediated via both MT1 and MT2 melatonin receptors. Melatonin exposure activates the PI3K/AKT signaling pathway and its inhibition attenuates the stimulatory effect of melatonin on StAR expression. Moreover, siRNA-mediated knockdown of StAR abolishes melatonin-induced P4 production. Importantly, clinical analyses demonstrate that melatonin levels in human follicular fluid are positively correlated with P4 levels in serum. By illustrating the potential physiological role of melatonin in the regulation of StAR expression and P4 production in hGL cells, our results may serve to improve current strategies used to treat clinical infertility.