LEP and polycystic ovary syndrome: In particular, it has been found that: 1) Leptin antagonizes insulin action in human granulosa cells and thereby inhibits their gonadotropin-stimulated progesterone production [9]; 2) Leptin stimulates the release of proinflamatory cytokines and prostaglandins in human placenta [4]; 3) High serum and follicular fluid leptin may account for decreased fertilization, implantation and pregnancy rates of IVF in PCOS women [10].