Dose-response studies of acid secretion after administration of tetragastrin. Studies in duodenal ulcer patients before and after highly selective vagotomy, hemigastrectomy and truncal vagotomy plus antrectomy.

Dose-response studies to tetragastrin were performed in patients with duodenal ulcer before and after highly selective vagotomy, hemigastrectomy and truncal vagotomy plus antrectomy. The calculated maximal response and the dose necessary to elicit 50 percent of that response (D50) were calculated by linear transformation of the results. Both highly selective vagotomy and hemigastrectomy were followed by a significant decrease in the stimulated acid output, characterized by a decrease in the calculated maximal response, but no change in the sensitivity of the parietal cells (D50) was observed. This indicates a noncompetitive reduction in the acid output. The calculated maximal response could not be restored to preoperative values by increasing the dose of stimulant. Truncal vagotomy plus antrectomy was followed by severe alteration in gastric physiology, and no linear transformation of the acid output could be made. This investigation shows that maximal acid output was obtained by the same dose of stimulant before and after all three operations studied. Therefore it is not necessary to increase the dose in postvagotomy acid studies.