Glucagon (GCG) - Marker for pancreatic alpha-cells

Glucagon is a peptide hormone specifically produced by the alpha cells of the pancreatic islets of Langerhans. Glucagon has the opposite effect of insulin, and is secreted when blood glucose levels become too low. Secretion of glucagon stimulates the liver to convert glycogen into glucose and release it to the blood stream. Glucagon is derived from a pre-protein that is cleaved into four distinct and biologically active peptides, out of which glucagon is one.