GIP and obesity due to melanocortin 4 receptor deficiency: GIP(3-30)NH2 has been infused in both healthy individuals (16, 22, 24, 75), patients with type 1 diabetes (77), type 2 diabetes (78, p. 2) with or without obesity (79), acromegaly (80), before and after gastric bypass surgeries (79), and in totally pancreatectomized patients (81).