Pentagastrin dose-response in peptic ulcer disease.

Stepwise increasing doses of pentagastrin (0.166, 1, and 6 mug/kg-hr) were given to 21 healthy volunteers (HV), 22 patients without peptic ulcer disease (MI), and 22, 18, and 19 patients with duodenal (DU), pyloric (PU), and gastric ulcer (GU) respectively. Maximal response (Vmax) and half maximal dose of pentagastrin (Km) were calculated for both acid and pepsin. The ability to secrete acid and pepsin was in PU and GU slightly higher and lower, respectively, than in the non-ulcer groups. Markedly elevated values were found in DU, and the pepsin secretion was relatively more increased than that of acid. The values for Km suggested a different behavior of the chief cells and the parietal cells in DU. Whereas the sensitivity of the parietal cells appeared to be abnormally high, that of the chief cells tended to be lower than normal. The discrimination between DU and the non-ulcer groups was better by estimation of pepsin than of acid secretion and tended to improve with increasing stimulation. Superiority was however, found for a submaximal dose of pentagastrin for acid secretion. No superiority in discrimination between groups was found for Vmax. Km was poorly reproducible for acid and pepsin and showed little diagnostic significance. The study suggests that pentagastrin dose-response does not provide more diagnostic information than a single dose (1 mug/kg-hr), which is maximal for pepsin and submaximal for acid.