[Effect of histamine H2-antagonists on serum gastrin levels in gastric lumen-perfused rats].
The effect of histamine H2-antagonists on serum gastrin concentration and histamine-stimulated gastric acid secretion was studied in gastric lumen-perfused rats in which changes in the intragastric pH were limited by using 2.5 mM propionate-succinate buffer as perfusate. The gastric acid secretion was measured by the titration of the acidity of gastric juice with 0.05 N NaOH. The serum gastrin levels were determined in the blood that was obtained simultaneously with gastric juice by radioimmunoassay. The gastric acid secretion was inhibited by these histamine H2-antagonists--cimetidine, famotidine, ranitidine and TZU-0460 administered intravenously. Within the dose-response range of the inhibition of gastric acid secretion, cimetidine and ranitidine increased significantly the serum gastrin levels, but famotidine and TZU-0460 did not. The doses of famotidine and TZU-0460 which were used to increase the serum gastrin levels were found to be higher than those for the maximal inhibition of gastric acid secretion. They also presented a dose-response curve to the serum gastrin levels similar to cimetidine and ranitidine. The findings suggest that histamine H2-antagonists have a potency to increase serum gastrin levels to that of the inhibition of gastric acid secretion.
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005744:Gastric Acid / Q000378:metabolism; D005755:Gastrins / Q000097:blood* / Q000378:metabolism; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D008297:Male; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains
D005755:Gastrins; D006635:Histamine H2 Antagonists