Interestingly, plasma FGF21, and hepatic and adipose tissue Fgf21 mRNA levels in Nrf2-deficient mice are higher than those in wild-type mice; given the beneficial role of FGF21 on metabolic syndrome and obesity, it is postulated that Nrf2 deficiency protects from an obesity-induced metabolic syndrome phenotype, in part by inducing production of FGF21 [119]. This evidence concerns the gene FGF21 and obesity due to melanocortin 4 receptor deficiency.