In C57BL/6J (B6) obese mice induced by genetic obesity (db/db) and high-fat and high-sugar diet, nicotine inhibited the increase of F4/80 in obesity-induced inflammation and the levels of proinflammatory cytokines such as TNF-α, IL-6, IL-1β and iNOS in serum (Wang et al., 2011). This evidence concerns the gene IL6 and obesity due to melanocortin 4 receptor deficiency.