Acid gastric secretory responses to histamine, crude porcine gastrin and pentagastrin in rats

Abstract The log dose-response curves for graded doses of the secretagogues porcine gastrin (a partially purified sample; the crude and its gastrin II equivalent), histamine, and a gastrin pentapeptide (pentagastrin) on the perfused stomachs of urethanized rats are parallel. On weight basis, pentagastrin is 60 times and histamine four times more active than the crude porcine gastrin preparation. The partially purified porcine gastrin sample is six times more potent than histamine but half as potent as pentagastrin. On molar basis gastrin (as the pure porcine gastrin II) has 3000 times the activity of histamine dihydrochloride and 5000 times that of the histamine base. Gastrin is 50 times more potent than pentagastrin. Gastrin and pentagastrin are more potent and have less undesirable side-effects than histamine.