Disturbances in this regulation in relation to cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1), hormones that regulate appetite and food intake, promote weight loss, and improve hyperglycemia, may be important in the context of the pathomechanism of obesity [198,199,200,201,202,203]. The gene discussed is GCG; the disease is obesity due to melanocortin 4 receptor deficiency.