Correspondingly, it is ablation of ARC POMC, not NTS POMC neurons, which is required for the development of obesity, increased fat mass and glucose intolerance (94), with the former neurons being stimulated by leptin (95), while the latter are stimulated by cholecystokinin (CCK) and inhibited by opioids (96). Here, CCK is linked to obesity due to melanocortin 4 receptor deficiency.