EFFECT OF OCCLUDING THE PYLORUS ON INTRAORAL INTAKE - A TEST OF THE GASTRIC HYPOTHESIS OF MEAL TERMINATION

Meal size does not change in response to food being restricted to the stomach by occlusion of the pylorus. This result has been used as evid ence for a gastric model of meal termination where feedback arising so lely from the stomach is taken to underlie satiation. Such data provid e support for the gastric model, however, only if the rate of gastric emptying during ingestion in the unoccluded condition is slow, such th at comparable amounts of food would be found in the stomach at the end of the meal in both the pylorus-occluded and unoccluded conditions. T o evaluate this issue directly, rats were implanted with pyloric cuffs and gastric cannulas and given an intraoral intake test of a 10.5% gl ucose solution with either the pylorus occluded or unoccluded. At the end of each intraoral intake test, the content of the stomach was remo ved via the gastric cannula and it's volume and concentration measured . Occlusion of the pylorus did not change meal size, but both the volu me and grams of glucose solute found in the stomach were substantially greater in the pylorus-occluded condition. These results are not cons istent with the hypothesis that the stomach is the sole source of inhi bitory signals that terminate a meal. Cumulative intake would appear t o be accurately tracked regardless of its distribution within the dige stive tract.