Nicotinamide and its metabolite N1-Methylnicotinamide alleviate endocrine and metabolic abnormalities in adipose and ovarian tissues in rat model of Polycystic Ovary Syndrome

Polycystic Ovary Syndrome (PCOS), as a common endocrine disorder is accompanied by hyperandrogenism, insulin resistance, ovulation problems, and infertility. Various types of off-label drugs like metformin have been used for the management of targeted problems caused by PCOS such as insulin resistance and hyperandrogenism. Nicotinamide (NAM) acts as a substrate of visfatin and Nicotinamide N-Methyltransferase (NNMT) leading to the generation of Nicotinamide Adenine Dinucleotide (NAD) and N1-Methylnicotinamide (MNAM), respectively. MNAM is known as an anti-inflammatory, anti-thrombosis, and anti-diabetic agent. In this study, the effects of NAM and MNAM on metabolic and endocrine abnormalities were evaluated in the adipose and ovarian tissues of a letrozole-induced rat model of PCOS. Our results showed that MNAM and NAM reversed abnormal estrous cycle and reduced the serum testosterone levels and CYP17A1 gene expression. Furthermore, all therapeutic factors improved HOMA-IR after treatment and NAM significantly increased the expression of GLUT4 and decreased the gene expression of visfatin. Also, MNAM diminished the gene expression of visfatin and resistin. It is noteworthy that all the therapeutic factors successfully activated the AMPK. In summary, this study is the first study reported beneficial effects of NAM and MNAM on the treatment of PCOS. Additionally, the alleviative effects of our therapeutic factors may be partially mediated by the AMPK-dependent manner due to the contribution of the AMPK in the expression of CYP17A1, visfatin, resistin, and GLUT4. Although more studies are required to unravel the exact mode of actions of MNAM and NAM in the PCOS, the findings of the current study shed light on an urgent need for discovering novel therapeutic pharmaceuticals regarding the treatment of PCOS.