G6PD and obesity due to melanocortin 4 receptor deficiency: Constitutively increased NADPH levels that occurred as a result of global overexpression of G6PD in mice stimulated NADPH oxidase activity in macrophages and increased inflammation [39,40], while constitutively increased NADPH levels in white adipose tissue (WAT) stimulated excessive fatty acid synthesis, obesity [41], and type 2 diabetes [42,43].