NAMPT and polycystic ovary syndrome: In this study, we have measured circulating leptin and visfatin levels and FF-leptin and FF-visfatin in a selected group of Caucasian Southern Italian nonoverweight women with PCOS (NOW-PCOS) undergoing in vitro fertilization/embryo transfer (IVF) in order to better understand the interrelationships, if any, between both cytokines and fertilization rate.