Gastric emptying and cholecystokinin in the control of food intake in suckling rats.

The rate of gastric emptying was determined in three-day old suckling rats. The gastric loads were given by gavage, and, after from 5 to 100 min, emptying was determined by removing the stomach and weighing the contents. Results were expressed as percentage of load still remaining in the stomach at one hour. The gastric loads in increasing order of speed of emptying were 1.0 M Na acetate, heavy cream, 0.5 M NaCl, milk, corn oil, 0.15 M lactose, 0.3 M glucose, 0.15 M NaCl, acidic water, and water. The rate of emptying was compared to the effectiveness in previous experiments of the same gastric loads in depressing intake. There was no significant correlation between rate of gastric emptying of the loads and their effectiveness in producing satiety. The octapeptide of cholecystokinin (80 Ivy dog units or 2.7 micrograms/kg i.p.) significantly depressed intake (measured as weight gain) of suckling rats of 1 1/2 hours, but the same dose did not slow gastric emptying. These findings indicate that rate of gastric emptying does not determine satiety in the suckling rat.