Gastric emptying and postprandial duodenogastric reflux in pylorectomized dogs.

A two-marker technique was used to determine gastric emptying rate and postprandial duodenogastric reflux rate without transpyloric intubation. The fractional gastric emptying rate in five dogs with normal pylorus was 3.0 +/- 0.3 (SE) X 10(-2)/min. In three dogs with circular pylorectomy, it was 5.8 +/- 0.8 X 10(-2)/min (P less than 0.01). The duodenogastric reflux rates were 0.72 +/- 0.23 (SE) ml/min and 3.21 +/- 0.97 ml/min. (P less than 0.05). The percentage of the test meal that by to-and-fro movements across the pylorus was emptied more than once was 2.3 +/- 1.0 (SE) in normal dogs and 15.5 +/- 2.4 after pylorectomy (P less than 0.005). Because the higher emptying rate was accompanied by more to-and-fro movements, the amount of the meal remaining in the stomach, and thus net gastric emptying, was similar in both groups. It is concluded that pylorectomy increases both reflux rate and emptying rate. This effect on emptying can only be detected by a method that includes the measurement of to-and-fro movements across the pylorus. The pylorus thus appears to prevent postprandial duodenogastric reflux and to slow gastric emptying.