Description
Glucagon is a peptide hormone secreted from the alpha cells of the pancreatic Islets of Langerhans.
The peptide consists of 29 amino acid residues and derives from the precursor proglucagon. As a counterregulatory hormone for insulin, glucagon plays a critical role in maintaining glucose homeostasis in-vivo in both animals and humans by stimulating hepatic glucose production. Glucagon acts as a glucose-mobilizing hormone. High plasma glucose concentrations stimulating insulin secretion from pancreatic beta cells, inhibit glucagon secretion whereas low plasma glucose concentrations represent one of the most potent glucagon secretory stimuli. Hypoglycemia (low glucose level) is physiologically the most potent secretory stimulus and the best-known action of glucagon. It stimulates glucose production in the liver and thereby enables adequate plasma glucose concentrations. Glucagon has a crucial role in the pathophysiology of diabetes, obesity and hepatic steatosis, which is discussed vastly in literature. Proglucagon is a precursor of glucagon, which via post-translational processes produces various peptides like glicentin and oxyntomodulin which have distinct and complementary biological functions.