GCG

Gene summary

The protein encoded by this gene is a proglucagon precursor 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 in the liver. In addition, glucagon promotes lipolysis and ketone body formation during prolonged fasting or stress. Glucagon secretion is stimulated by low blood glucose and inhibited by high glucose or insulin. Glucagon is a ligand for a specific G-protein linked receptor called glucagon receptor, which activates the Gs protein-adenylate cyclase-cAMP-protein kinase A signaling pathway to regulate carbohydrate and lipid metabolism. Two of the other peptides, glucagon-like peptide-1 and glucagon-like peptide-2, are produced by the intestinal L-cells and secreted in response to nutrient ingestion, where they function as important regulators of glucose metabolism and intestinal physiology. Glucagon-like peptide-1 enhances glucose-dependent insulin secretion, suppresses glucagon release, slows gastric emptying, and promotes satiety, making it a key incretin hormone for maintaining postprandial glucose levels. Glucagon-like peptide-2 primarily acts on the gut, promoting intestinal growth, enhancing nutrient absorption, and supporting mucosal integrity. Both peptides exert their effects through specific G-protein-coupled receptors, glucagon-like peptide-1 receptor and glucagon-like peptide-2 receptor, respectively, and analogs of glucagon-like peptide-1 are used clinically for the treatment of type 2 diabetes and obesity. The fourth peptide is similar to glicentin, an active enteroglucagon produced in the intestinal L-cells. This peptide is thought to have multiple roles in gastrointestinal physiology, including stimulating intestinal growth, modulating gut motility, and influencing the secretion of other gut hormones. Although its precise functions are less well-characterized than those of glucagon, glucagon-like peptide-1, or glucagon-like peptide-2, glicentin-like peptides may contribute to postprandial digestive processes and the coordination of nutrient absorption. [provided by RefSeq, Mar 2026]