RETN and obesity due to melanocortin 4 receptor deficiency: We further investigated differential gene expression in the visceral (gonadal) adipose tissue in these offspring, including the expression of Lep (leptin), Pparg (peroxisome proliferator activator receptor gamma) and Irs1 (insulin receptor substrate 1) which enhance insulin signaling in WAT, Retn (resistin) which enhances liver glucose output and is elevated during obesity, Rbp4 (retinol binding protein 4) which inhibits liver insulin action, and Glut4 (glucose transporter 4) which is the transporter that mediates blood glucose uptake into adipocytes in response to insulin.