Effects of cholecystokinin-octapeptide (CCK-8) on food intake and gastric emptying in man.

Food intake and gastric emptying were measured simultaneously after cholecystokinin-octapeptide (CCK-8) and saline infusions in order to test the hypothesis that reduction in gastric emptying mediates the effect of CCK-8 on food intake. Each of twelve nonobese healthy men received intravenous infusions of CCK-8 and saline on separate nonconsecutive days after they had consumed 500 g of tomato soup tagged with technetium-99-DTPA. Intake of a test meal was measured 20 min after consumption of the soup while gastric emptying was simultaneously monitored by gamma emission scintigraphy of the soup. Food intake and gastric emptying of the soup were both significantly reduced by CCK-8 infusions in comparison to saline. There was a significant correlation between the amount of the test meal eaten and the amount of soup emptied during the period the test meal was being eaten, but not before the meal, only on days when CCK-8 was infused. Differences in intakes between days when saline was infused and days when CCK-8 was infused did not correlate with differences in gastric emptying of soup. These results suggest that CCK may amplify signals of satiety in proportion to the fullness of the stomach. Gastric emptying per se may not mediate the effects of CCK-8 on food intake.