Pyloroplasty does not disrupt liquid phase gastric emptying or CCK-induced satiety

To assess the hypothesis that cholecystokinin (CCK) induces satiety by constricting the pylorus and inhibiting the rate of gastric emptying, we impaired pyloric function in 8 experimental animals using a Heincke-Mikulicz pyloroplasty procedure. Liquid phase gastric emptying was measured with a double-sampling procedure. We found that pyloroplasty did not disrupt the pattern of gastric emptying of saline or nutrient under control conditions. CCK also showed emptying in both pyloroplasty and control animals. Finally, pyloroplasty did not affect the ability of CCK to induce satiety. We provide functional and morphological evidence that the pyloroplasty procedure successfully impaired constriction of the pyloric sphincter. These findings suggest that the pylorus is not critical to the control of liquid phase emptying and, together with the absence of a pyloroplasty effect on CCK-induced satiety, seriously question the adequacy of the pyloric mediation hypothesis.