Glucagon (GCG)

Glucagon has a major role in maintaining normal concentrations of glucose in blood, and is often described as having the opposite effect of insulin. That is, glucagon has the effect of increasing blood glucose levels. Glucagon is a linear peptide of 29 amino acids. Its primary sequence is almost perfectly conserved among vertebrates, and it is structurally related to the secretin family of peptide hormones.

Glucagon is synthesized as proglucagon and proteolytically processed to yield glucagon within alpha cells of the pancreatic islets. Proglucagon is also expressed within the intestinal tract, where it is processed not into glucagon, but to a family of glucagon-like peptides (enteroglucagon).