Cholecystokinin and satiety in pigs.

Twenty-three pigs, 1-3 mo of age, were fitted variously with intraperitoneal, intrajugular, intraportal, and intraduodenal catheters. After a 4-h fast, porcine cholecystokinin (CCK), 5-40 Ivy dog units/kg body wt (IDU/kg); caerulein, 0.25-2 micrograms/kg; or the octapeptide of cholecystokinin (CCK-OP), 5-40 IDU/kg, was given parenterally; or 2-5% sodium oleate or 5% protein hydrolysate (5 ml/kg) was injected intraduodenally. Pelleted feed intake was then measured for 10 min. Food intake was depressed in a dose-related fashion in all instances as compared to after 0.9% NaCl control injections. For example, feed consumption following 5 and 40 IDU/kg of CCK intrajugularly was 84 +/- 2 and 6 +/- 4 (SE) %, respectively, of control intake. Intraportal infusion produced a greater depression of feeding. A conditioned taste aversion could not be formed to CCK, caerulein, or CCK-OP. Sodium oleate or protein hydrolysate, releasers of endogenous CCK, depressed feeding, and this satiety effect was attenuated when given with 0.5% tetracaine. The results support the hypothesis that CCK participates in rapid, presumably preabsorptive, satiety.