Pepsin and acid secretions during and after gastric operations in patients with duodenal ulcer.

Measurement of gastric pepsin and acid secretion was performed before, during and after selective vagotomy with antrectomy (SVA) and Billroth I gastrectomy (B-I) in 20 patients with a duodenal ulcer. Preoperative pepsin concentration increased during operation and decreased gradually 72 hours after SVA and 1 to 3 months after B-I. Although the pepsin concentration decreased substantially, it was never less than 70% of the preoperative level in both groups. Acid concentration decreased immediately after vagotomy in the SVA group and decreased gradually after 72 hours in the B-I group. Although there was a notable increase in the pH in both groups after operation, a pH of 5 was never reached. Decrease in gastric secretory volume (about 50%) was approximately equal in both groups. It appears that any increase in acid secretion occurring after vagotomy or gastrectomy may be sufficient to activate high-and low-pH-acting pepsins. Extravagal and extraantral stimulation of gastric pepsin secretion after operation should be considered an important etiologic factor in the pathogenesis of recurrent ulcer.