Nejabati et al. demonstrated that in letrozole-induced polycystic ovary syndrome (PCOS) in rats, compared with the control group, supplementation with NAM or the NAM metabolite N1-methylnicotinamide caused a reversal of abnormal estrus, a reduction in gene expression levels of the rate-limiting enzyme CYP17A1 that regulates androgen production and serum testosterone levels through activation of AMPK-mediated pathways [14]. The gene discussed is CYP17A1; the disease is polycystic ovary syndrome.