Secretin-like bioactivity in the duodenal mucosa in patients with peptic ulcer and chronic pancreatitis.

Biopsy specimens of the duodenal mucosa were assayed to determine their secretin-like activity in 9 controls, 9 patients with gastric ulcer, 19 patients with duodenal ulcer, 4 patients with gastric and duodenal ulcer, and 13 patients with chronic pancreatitis. The bioassay of secretin was done on the pancreatic secretion in anesthetized rats. The sensitivity was in the orcer of 0.0625 CHR unit/rat (4 ng/rat). In the range between 0.0625 and 0.5 CHR units a satisfactory dose dependency was recognized. The following results were obtained. 1) The level of duodenal mucosal secretin-like activity in patients with gastric ulcer was the same as that in the controls, but was elevated in 32% of the patients with duodenal ulcer, 50% of those with gastric and duodenal ulcer, and 8% of those with chronic pancreatitis. 2) The high level of secretin-like activity noted in patients with duodenal ulcer was suspected to be related to the hypersecretion of gastric acid which is characteristic of this disease, but there was no correlation between gastric acid secretion and secretin-like activity in the duodenal mucosa.