Glucagon
A 29 amino acid peptide hormone produced by pancreatic alpha cells that raises blood glucose by stimulating glycogenolysis and gluconeogenesis in the liver. Synthetic glucagon is an approved emergency treatment for severe hypoglycaemia. Glucagon receptors are also targets in investigational triple agonist therapies.
Technical Context
Glucagon (29 aa) is produced by pancreatic alpha cells from the same proglucagon gene that produces GLP-1 and GLP-2 in L-cells (tissue-specific processing by different prohormone convertases). The glucagon receptor (GCGR) is a class B GPCR coupled to Gαs, activating cAMP-mediated hepatic glycogenolysis and gluconeogenesis to raise blood glucose. Glucagon is the primary counter-regulatory hormone to insulin. Therapeutic applications include: emergency hypoglycaemia treatment (1mg IM/SC or nasal powder), and as a diagnostic agent for GI imaging (smooth muscle relaxation). In the context of next-generation metabolic drugs, glucagon receptor agonism (as part of triple agonists) is being explored for its potential to increase energy expenditure and promote hepatic fat oxidation.