Glucagon Radioimmunoassay

Glucagon is a 29 amino acids straight chain peptide produced in the pancreatic a-cells. Glucagon is cleaved out from preproglucagon with 159 amino acids. The amino acid sequence of glucagon is found in glicentin, a 69 amino acid peptide. Glicentin has been proposed to be a biosynthetic intermediate for pancreatic and gut glucagon. Glucagon is involved in carbohydrate, fat and protein metabolism. Basal amounts of glucagon are essential for the maintenance of normoglycemia and a physiological role for glucagon is to prevent hypoglycemia. Increases in the plasma glucagon level affect glucose production first by stimulating a transient phase of glycogenolysis and then a prolonged period of glyconeogenesis. A sustained increase in the glucagon level continues to modulate hepatic glucose production. Glucagon also plays a role in the amino acid metabolism. Elevation of glucagon in plasma decreases amino acids whereas glucagon deficiency increases amino acids. The amino acid sequence of human pancreatic glucagon: His-Ser-Gln-Gly-Thr-Phe-Thr-Ser-Asp-Tyr-Ser-Lys-Tyr-Leu-Asp-Ser-Arg-Arg-Ala-Gln-Asp-Phe-Val-Gln-Trp-Leu-Met-Asn-Thr.