Continuous light for a long time creates similar characteristics of human PCOS in rats, including persistent estrus, anovulation, ovarian cysts, and increased levels of estrogen and androgen in plasma [21].Therefore, in order to remove the effect of exogenous sex hormones for induction of PCOS such as testosterone or estradiol on the expression of MC4R or kiss1 mRNAs, we selected constant light-induced PCOS model. Here, MC4R is linked to polycystic ovary syndrome.