Interaction between CCK and a preload on reduction of food intake is mediated by CCK-A receptors in humans

Cholecystokinin (CCK) interacts with neural signals to induce satiety in se veral species, but the mechanisms are unclear. We therefore tested the hypo thesis that alimentary CCK (CCK-A) receptors mediate the interaction of CCK with an appetizer on food intake in humans. CCK octapeptide (CCK-8, 0.75 m u g infused over 10 min) or saline (placebo) with concomitant infusions of saline (placebo) or loxiglumide, a specific CCK-A antagonist, was infused i nto 16 healthy men with use of a double-blind, four-period design. All subj ects received a standard 400-ml appetizer (amounting to 154 kcal) but were free to eat and drink thereafter as much as they wished. The effect of thes e infusions on feelings of hunger and satiety and on food intake was quanti fied. CCK-8 induced a reduction in calorie intake (P < 0.05) compared with saline. Furthermore, a decrease in hunger feelings (P < 0.05, saline-CCK-8 vs. all other treatments) and an increase in fullness were observed. These effects were antagonized for hunger and fullness by loxiglumide. We conclud e that CCK-8 interacts with an appetizer to modulate satiety in humans. The se effects are mediated by CCK-A receptors.