Gastric emptying in young pigs.

1. Gastric emptying in young pigs has been studied by using a serial test meal procedure.2. Phenol red was used as a reference substance. In acute experiments the recovery of phenol red from the stomach with the pylorus occluded was 94.8 +/- 2.2 (S.E.)% of that introduced.3. Gastric emptying was examined in seven fasted conscious pigs provided with a chronic gastric cannula. After emptying the stomach 500 ml. of a liquid meal containing 20 g citrus pectin, 35.0 g sucrose and 100 mg phenol red made up to 1 l. was introduced. After 5-60 min the meal was withdrawn, the volume of meal that had left the stomach was assessed from the recovery of phenol red and the secretion of gastric juice was calculated from the dilution of phenol red and the rate of emptying. After an initial very rapid outflow, the rate of emptying fell with time, as did the rate of secretion.4. In three pigs 200, 400, 600 or 800 ml. meal was introduced into the stomach and the stomach was emptied 20 min later. The rate of gastric emptying varied directly with the volume of meal introduced.5. Atropine sulphate, 0.5 mg/kg body weight, injected I.M. 30 min before the test, greatly inhibited gastric emptying and secretion.