Gastric inhibitory polypeptide (GIP).

As long ago as 1930, Kosaka and Lim proposed a humoral agent capable of inhibiting gastric acid secretion after a meal. They coined the term enterogastrone. Using crude preparations of cholecystokinin-pancreozymin (CCK PZ) in dogs they were able to inhibit the acid secretion normally stimulated by a meat meal or histamine. They went on to experiment with duodenal extracts, prepared after the instillation into the duodenum of olive oil, and found a similar effect to that seen with crude CCK PZ. The effects of similar crude preparations ofCCK PZ in the dog were confirmed by Brown and Pederson in 1970, but further purification of this material led to a diminution of the acid inhibitory effect (Brown and Pederson, 1970). In 1971, Brown and Dryburgh purified and sequenced this gastric inhibitory fraction and found it to be a polypeptide quite distinct from other known peptide hormones. By virtue of its acid inhibitory properties they named it gastric inhibitory polypeptide, GIP.