Parietal and chief cell sensitivity to histamine and pentagastrin stimulation before and after cimetidine treatment in healthy subjects.

Gastric acid and pepsin output in response to 2.5 and 25.6 micrograms . kg-1h-1 of histamine dihydrochloride and 0.10 and 6.0 micrograms . kg-1h-1 of pentagastrin was studied before and after cessation of 4 weeks of cimetidine treatment, 1 g/day, in 10 healthy volunteers. Acid output in response to the low dose of histamine increased significantly from an average of 6.7 mmol +/- 1.3 mmol (S.E.M.) before to 10.1 mmol +/- 0.9 mmol after treatment (p = 0.02), whereas acid output in response to the maximal dose of histamine was not significantly different. Parietal cell sensitivity to histamine stimulation increased significantly after the treatment period from a mean of 28.2% +/- 3.2% before treatment to 49.3% +/- 2.8% afterwards (p less than 0.01). The results indicate augmented parietal cell sensitivity in response to histamine stimulation after withdrawal of cimetidine. Both acid output in response to the two doses of pentagastrin and parietal cell sensitivity to pentagastrin stimulation were not significantly different after cessation of cimetidine treatment. Pepsin output and chief cell sensitivity to histamine and pentagastrin stimulation were not significantly influenced by cimetidine treatment.