[Advances in gastrointestinal hormones: cholecystokinin]

Cholecystokinin (CCK) and gastrin are members of an important family of gastroenteropancreatic polypeptides. Distribution of CCK both in the digestive system and central and peripheral nervous structures correlates with the variety of its actions; more than a classic hormone, CCK is a peptidergic neurotransmitter. CCK plays a predominant role in multiple digestive functions: contraction and emptying of the gallbladder, stimulation of pancreatic secretion of enzymes, delay of gastric emptying, diminution of gastric acid secretion, regulation of insulin secretion, reduction of food intake, etc. Distinction between pharmacologic and physiologic effects has been difficult in all of these areas. Modern technological procedures have generated significant progresses: reliable plasmatic bioassay, understanding of molecular heterogeneity, identification and characterization of receptors and their subtypes, agonists and antagonists, some of them currently available for research studies. The integrationist perspective of normal and pathological physiology has been considerably enhanced. Therapeutic use of CCK and its derivatives in some specific problems, i.e. obesity and anorexia, remains incipient and restricted.