For example, central administration of insulin provokes hyperpolarization of ARC-residing AgRP and POMC neurons [6], whereas neuron-specific ablation of insulin receptors is associated with diet-induced obesity [7], and ablation from AgRP, but not POMC neurons, alters hepatic glucose production [8,9]. The gene discussed is POMC; the disease is obesity due to melanocortin 4 receptor deficiency.