Glucagon was discovered in 1922 as a hyperglycemic factor in the pancreas. During its
early history up to 1970, glucagon was shown to increase circulating glucose through
stimulating glycogenolysis in the liver. It was also shown to be a constituent of islet non-β
cells and to signal through G protein coupled receptors and cyclic AMP. Furthermore, its
chemical characteristics, including amino acid sequence, and its processing from the
preproglucagon gene had been established. During the modern research during the last 40 …