Consistent outcomes in animal models comprise loss of appetitive, locomotor, and somatotropic regulation by exogenous ghrelin; modest reduction of body weight, IGF-I concentrations, and GH pulses in the female animal; increased fat oxidation; a rise in mean arterial blood pressure; reduced obesity and improved glucose tolerance, but with a potentially higher risk of hypoglycemia during prolonged fasting; and decreased development of fatty diet-induced diabetes mellitus [164–168, 174–185]. The gene discussed is GHRL; the disease is obesity due to melanocortin 4 receptor deficiency.