Glucagon receptors are a family of G protein-coupled receptors (GPCRs) comprised of six receptor subtypes: glucagon, glucagon-like peptide 1 (GLP-1), glucagon-like peptide 2 (GLP-2), gastric inhibitory polypeptide (GIP), growth hormone-releasing hormone (GHRH), and secretin receptors. Glucagon receptors play a major role in the regulation of blood glucose, insulin release, appetite regulation, and other various CNS effects. Glucagon receptor mutations in humans is associated with type II diabetes, hypoglycemia, and islet cell tumors. There are therapeutic applications for glucose receptors in treating diabetes.