Introduction Cholecystokinin (CCK) and the CCK1 receptor play an important role in both gastric emptying1 and the control of food intake in man.2 Accordingly CCK antagonism increases feeling of hunger, decreases feelings of fullness2 and leads to accelerated gastric emptying.1 It is not known if the magnitude of physiological response to CCK antagonism relates to the magnitude of changes in reported hunger and fullness elicited by a test meal.

Objectives To determine if the magnitude of changes in gastric emptying relate to the magnitude of changes in feelings of hunger and fullness, in response to a test meal, after CCK1 receptor antagonism.

Methods 25 healthy subjects (12 female, mean age 23, mean BMI 23.7) underwent six gastric emptying studies of a nutrient test meal (milk) using the ¹³C acetate breath test. On three occasions they were pre-treated with the CCK1 receptor antagonist, dexloxiglumide 600 mg. Subjects rated feelings if hunger and fullness in a visual analogue scale at 5-min intervals throughout the duration of the study (45 min). Average area under curve (AUC) for hunger and fullness were recorded and scores for the upper quartile (UQ, with the biggest response to dexloxiglumide) were compared to those in the lowest quartile (LQ, with the least response to dexloxiglumide).

Results After dexloxiglumide, the mean per cent change in gastric emptying for the six greatest responders was 64±10 and for the six smallest responders 10±10. When the two groups were compared, no difference in per cent change in AUC was seen for reported hunger (UQ: 170±318 vs LQ: −33±232, p=0.31) or fullness (UQ: 167±137 vs LQ: 168±274).

Conclusion The magnitude of response to CCK1 receptor antagonism, as measured by change in gastric emptying rate, does not relate to changes in reported feelings of fullness or hunger after a test meal. This calls into question the physiological role of CCK in appetite control.