This peptide hormone induces gall bladder contraction and the release of pancreatic enzymes in the gut. Its function in the brain is not clear (By similarity). It also decreases food intake and regulates gastrointestinal physiological processes. In the small intestine, the major production site is around the vitelline diverticulum. By dietary protein, amino acids and medium-chain triacylglycerol. The precursor is cleaved by proteases to produce a number of active cholecystokinins. Belongs to the gastrin/cholecystokinin family.