Effect of liquid meals on duodenogastric reflux in humans.

In humans duodenogastric reflux and gastric emptying were measured simultaneously by a two-marker technique that avoids transpyloric intubation. The duodenal marker consisted of 99mTc-labeled Hepatobida and was infused intravenously at a constant rate. Hepatobida was cleared almost exclusively by the liver and entered the duodenum at a constant rate via the bile. The gastric marker consisted of 51CrCl2 and was used to measure total intragastric volume by the double-sampling technique. Duodenogastric reflux occurred both after meals and under fasting conditions. Reflux rate was on the average 13 times smaller than emptying rate. It was higher with a lipid than with a protein meal and was independent of the rate of gastric emptying. The gastric concentration and total amount of duodenal contents were higher after lipid than protein meals. Since gastric emptying of a protein meal was faster than emptying of a lipid meal, the increased gastric concentration and accumulation of duodenal contents after lipid meals are due to a slowed gastric clearing and increased reflux of duodenal contents. Under fasting conditions, the reflux was lower and the gastric concentration of duodenal contents was higher than with both types of meals. Hence regurgitated duodenal contents may cause more damage to the gastric mucosa under fasting conditions than postprandially.