Effects of the CCK receptor antagonist MK-329 on food intake in pigs.

The cholecystokinin (CCK) receptor antagonist MK-329 (previously L364,718) was administered intravenously (IV) (17.5-140 micrograms/kg) to pigs trained to make operant responses for food reinforcements after 4 hr of food deprivation. MK-329 produced a dose-related increase in food intake during the 2-hr test period, with maximum increases occurring at a dose of 70 micrograms/kg. CCK (1 micrograms/kg IV) produced a short-term reduction in feeding and this effect was completely abolished by pretreating the animals with MK-329 (70 micrograms/kg). The present results lend support to the hypothesis that endogenous CCK is involved in satiety.