Physiopathological heterogeneity of the duodenal mechanisms that inhibit gastric acid secretion in duodenal ulcer patients.

The effect of duodenal acidification on pentagastrin-stimulated gastric acid secretion was studied in 43 duodenal ulcer patients and in 17 normal controls. Three types of responses were observed: group A, no inhibition of gastric acid secretion occurred in 17 (40%) ulcer patients and in three (18%) controls (p less than 0.05); group B, inhibition of gastric acidity occurred in seven (16%) ulcer patients and in 12 (71%) controls (p less than 0.05), and group C, retarded gastric acid inhibition occurred in 19 (44%) duodenal ulcer patients and in 2 (12%) controls (p less than 0.05). Secretin levels did not increase after duodenal acidification, the higher percentages of failure being observed in groups A and C (p less than 0.05). The pH of the duodenal aspirate was 4.9 +/- 2 and 7.7 +/- 1.4 in ulcer patients and controls, respectively (p less than 0.05), with the low levels being detected in groups A and C (4.7 +/- 2 and 5.3 +/- 2.1) compared to group B (7.3 +/- 1.7; p less than 0.05). The results show that responses of duodenal ulcer patients to duodenal acidification are heterogeneous, and that failure of gastric secretion inhibition and defective intraduodenal acid neutralization are related.