Proglucagon

Proglucagon is a protein that in humans is encoded by the GCG gene. It is a member of the glucagon family and plays a crucial role in glucose metabolism and homeostasis.

Structure

Proglucagon is a 160 amino acid peptide that is synthesized in the alpha cells of the pancreas and the L cells of the intestinal tract. It is processed by prohormone convertase 1 in the L cells to produce glucagon-like peptide 1 (GLP-1), glucagon-like peptide 2 (GLP-2), oxyntomodulin, and glicentin. In the alpha cells, it is processed by prohormone convertase 2 to produce glucagon.

Function

Proglucagon-derived peptides have diverse functions. Glucagon acts to increase blood glucose levels by promoting glycogenolysis and gluconeogenesis in the liver. GLP-1 and GLP-2 are secreted in response to food intake. GLP-1 enhances insulin secretion, inhibits glucagon secretion, slows gastric emptying, and suppresses appetite. GLP-2 stimulates growth and repair of the gut lining.

Clinical significance

Alterations in proglucagon processing and the actions of its derived peptides are implicated in several diseases, including type 2 diabetes, obesity, and short bowel syndrome. GLP-1 analogs and inhibitors of its degradation are used in the treatment of type 2 diabetes.

See also

• Glucagon
• Glucagon-like peptide 1
• Glucagon-like peptide 2
• Glycogenolysis
• Gluconeogenesis