Intravenous pentagastrin as a partial agonist of gastric secretion in man: evidence in favor of the existence of hormonal inhibitory sites
Prugh, M.F.; Schorr, B.A.; Vlahcevic, Z.R.; Makhlouf, G.M.
Gastroenterology 68(1): 45-49
1975
ISSN/ISBN: 0016-5085 PMID: 163778 Document Number: 82955
The gastric secretory response to prompt intravenous injection of pentagastrin was studied in 3 normal subjects and 3 patients with duodenal ulcer. The highest responses to pentagastrin and histamine were correlated. Pentagastrin, 0.5 mu g/kg bodyweight given by vein, could achieve the same extent of discrimination between individuals with a one-tenth the dosage as the subcutaneous route. Sensitivity to pentagastrin, expressed in the D50, was higher in patients. The highest response to pentagastrin given by vein was only 40% of the peak response to subcutaneously given histamine. Accordingly, intravenous pentagastrin acted as a partial agonist with an efficacy of about 0.4. The effect of prompt injection of pentagastrin contrasted with the effect of slow intravenous infusion, as well as with the effects of gastrin-17 given by either way. A model is proposed to account for these and related findings in other species.