Recent studies have suggested that Nrf2 can function in different manners; it can control the expression of genes whose protein products are involved in the detoxification and elimination of reactive oxidants and electrophilic agents through conjugative reactions, thereby enhancing cellular antioxidant capacity; it also plays an important role in the regulation of glucose and lipid metabolism in obesity (Nguyen et al., 2009; Tanaka et al., 2008). Here, NFE2L2 is linked to obesity due to melanocortin 4 receptor deficiency.