Glucagon is a single-chain polypeptide that contains 29 amino acid residues and has a molecular weight of 3,483. Glucagon is a hormone produced in the pancreas and it is used to raise very low blood sugar. Glucagon is also used in diagnostic testing of the stomach and other digestive organs. Glucagon increases blood glucose concentration and is used in the treatment of hypoglycemia. Glucagon acts only on liver glycogen, converting it to glucose. Glucagon administered through a parenteral route relaxes smooth muscle of the stomach, duodenum, small bowel, and colon.