Serum group I pepsinogens after consecutive stimulations with insulin and pentagastrin in unoperated duodenal ulcer patients and in duodenal ulcer patients after proximal gastric vagotomy.

Ten unoperated duodenal ulcer (DU) patients and 11 DU patients 1 year after proximal gastric vagotomy (PGV) were examined for gastric acid secretion and for serum group I pepsinogens (PG I) during basal conditions and after consecutive stimulations with insulin and pentagastrin. In unoperated DU patients insulin stimulation caused a significant increase both in gastric acid secretion and in serum PG I. In these patients a consecutive pentagastrin stimulation elicited a significant increase in gastric acid secretion but not in serum PG I. In patients after PGV, insulin stimulation caused a slight but significant increase in gastric acid secretion but not in serum PG I. In these patients a consecutive pentagastrin stimulation caused a significant increase both in gastric acid secretion and in serum PG I. Two of the operated patients had negative and nine had positive responses to the postoperative insulin test. According to this study, in consecutive stimulation with insulin and pentagastrin the effect of pentagastrin on serum PG I is inhibited by preceding insulin stimulation in DU patients. By PGV the effect of insulin on serum PG I is eliminated. and then a subsequent pentagastrin stimulation elicits a significant rise in serum PG I. As a test of the completeness of PGV, the serum PG I response to insulin-induced hypoglycemia seems to be less sensitive than the gastric acid response.