Effect of duodenal juice on pathogenesis of gastric ulcer

The purpose of the present study was to elucidate the effect of duodenal juice on development of gastric ulcer, in relation to changes of lipid composition and energy metabolism of the gastric mucosa in dogs. For regurgitation of duodenal juice and stagnation of gastric contents in the stomach, the duodenum was constricted below the papilla of Vater, accompanying with pyloroplasty and upper gastro-jejunostomy. Furthermore, to induce ischemia in the gastric mucosa, 0.5 ml of 1% formalin solution was injected into a descending branch of the left gastric artery. Three weeks later, U1 II-III gastric ulcer developed at the formalin injected area with severe gastritis but not with hyperacidity, and the histologic findings were similar to the one of a human gastric ulcer with hypoacidity. On assay of lipid composition in the gastric mucosa, lecithin decreased and both lysolecithin and NEFA increased, showing that lecithin of the gastric mucosa was decomposed by phospholipase A2 of the duodenal juice. In the gastric mucosa, ATP and energy charge decreased, and AMP and lactate increased, indicating that the energy metabolism was led to anaerobic glycolysis. These results revealed that the gastric mucosa becomes very fragile when duodenal juice regurgitates into the stomach and that gastric ulcer may develop even without hyperacidity when the microcirculation is disturbed in this condition.