Cholecystokinin (CCK) is a peptide hormone that, through specific receptors, induces pancreatic growth and enzyme secretion, smooth muscle contraction in the gall bladder and stomach, and modulates feeding and behavior. Lorglumide is a nonpeptidic antagonist of the CCK A receptor (CCK1; IC50 = 50 nM) that is 60-fold less effective at the CCK B receptor (CCK2; IC50 = 3 μM). It blocks CCK-mediated gut muscle contraction, pancreatic growth, and pancreatic secretion. Lorglumide is commonly used to study the roles of CCK1 in tissues and in animals.