Comparison of acid secretory responsiveness to gastrin heptadecapeptide and of gastrin heptadecapeptide pharmacokinetics in duodenal ulcer patients and normal subjects.

Serum gastrin concentrations and gastric acid secretion were measured during intravenous infusion of gastrin heptadecapeptide (G-17) (0, 7, 22.1, 70, 221, and 700 pmol/kg X h) in 15 duodenal ulcer patients and 15 healthy controls. Ulcer patients developed higher serum gastrin concentrations during G-17 infusion due to nearly twofold slower clearance of gastrin (8.8 vs. 15.7 ml/kg X min; P less than 0.01). Despite slower clearance of G-17, ulcer patients had plasma elimination half-times for G-17 similar to controls (6.0 vs. 6.1 min, respectively). Thus, calculated volume of distribution for G-17 was lower in ulcer patients than controls (78.5 vs. 140.7 ml/kg; P less than 0.025). For any serum gastrin during gastrin-17 infusion, acid secretion (millimoles per hour) was higher in ulcer patients than in controls. However, when acid secretion was expressed as a percentage of peak acid output to G-17 (to correct for differences in parietal cell mass), curves relating acid secretion to serum gastrin were identical in ulcer patients and controls.