The protein encoded by this gene is actually a preproprotein that is cleaved into four distinct mature peptides. One of these, glucagon, is a pancreatic hormone that counteracts the glucose-lowering action of insulin by stimulating glycogenolysis and gluconeogenesis. Glucagon is a ligand for a specific G-protein linked receptor whose signalling pathway controls cell proliferation. Glucagon is best known as the counter-regulatory hormone to insulin, and normal glucose homeostasis depends largely on the balanced secretion of insulin and glucagon from the pancreatic beta and alpha cells, respectively.
