Glucagon is a hormone secreted by the pancreas, the role of which is to stimulate the breakdown of glycogen into glucose.
Structure of glucagon
Glucagon has a relatively simple structure as it is a relatively small peptide containing only 29 amino acids. It is produced in the pancreas by the alpha cells of the islets of Langerhans.
Function of glucagon
Glucagon has a hormonal function that counters insulin, causing an increase in blood glucose (hyperglycaemic function). It hydrolyses glycogen in the liver to do this causing release of glucose molecules into the blood. This effect is called glycogenolysis.
Regulation of the action of insulin and glucagon maintains a correct blood glucose concentration appropriate for the body's efforts.
Glucagon is a relatively short peptide hormone. © brian0918, Wikimedia, public domain