Glucagon is a polypeptide hormone key to the regulation of glucose homeostasis. In imaging it has been used as an adjunct agent in nuclear medicine studies
Glucagon is a 29 amino acid polypeptide hormone that is enzymatically-derived from proglucagon, its precursor.
History and etymology
Unusually glucagon was named before it was discovered!
In 1922 Banting et al. found that crude pancreatic extracts given to children with diabetes produced a short-lived elevation of the serum glucose before insulin's desired hypoglycemic effect. It was postulated that an unknown substance, named glucagon, was responsible 3. It was only in 1955 that the polypeptide responsible was finally purified 1.