NOS3 and obesity due to melanocortin 4 receptor deficiency: In mice, it has been shown that a deficiency of endothelial nitric oxide synthase (eNOS−/−, NOS3) leads to an increased accumulation of liver fat, insulin resistance,36 and obesity,37 which recapitulates several features seen in humans with metabolic syndrome and is exacerbated by Western diet‐induced hepatic inflammation and fibrosis.25, 38