Satiety effects of cholecystokinin and ceruletide in lean and obese man

Cholecystokinin (CCK) has been shown to produce satiety not only in a variety of animal species but in man as well. In healthy humans, CCK reduces appetite and activation arising from the preparation of a meal, inhibits intake of liquid food in both non-obese and obese subjects, and decreases the intake of solid food. The closely related caerulein produces a similar reduction of solid food consumption in lean and, as suggested by preliminary results, in obese man. There is good evidence that the satiety effect of CCK depends on its inhibition of gastric emptying and the consequent gastric distension. In healthy man, the same dose of caerulein found to reduce food intake also slows gastric emptying of a semisolid meal. This effect seems to be relayed into the brain by afferent vagal fibers as in animals; selective gastric vagotomy blocks the satiety effect while pharmacological antagonism of vagal motor effects or lesions in the ventro-medial hypothalamus do not. Ongoing studies suggest that gastric vagotomy also blocks the satiety effects of caerulein in man. A critical role for CCK in the control of human feeding behavior seems certain.