The cholecystokinin (CCK) family of peptide hormones have been implicated in numerous important physiologic events. These appear to be mediated through 2 general classes of receptors, A (CCKAR)and B (CCKBR), based on their binding affinities for CCK/gastrin family peptides. Through binding to class A receptors, CCK is a major physiologic mediator of gallbladder contraction and pancreatic enzyme secretion. It appears to play a role in slowing gastric emptying, relaxation of the sphincter of Odd