Effects of omeprazole, famotidine, and ranitidine on the enzyme activities of carbonic anhydrase from bovine stomach in vitro and rat erythrocytes in vivo

Abstract

In this study, the effects of omeprazole, famotidine, and ranitidine on bovine stomach carbonic anhydrase (EC 4.2.1.1.) isoenzymes have been investigated in vitro. Bovine stomach carbonic anhydrase (CA) was purified from four different cell localisations of bovine stomach using affinity chromatography by Sepharose 4B-L-tyrosine sulphanilamide. The inhibition or activation effects of three different medical drugs on CA isoenzymes were determined using esterase activity and the CO2-hydratase method by plotting activity % vs. [medical drug]. The Ki values for omeprazole, famotidine, and ranitidine were determined in all localization CA, respectively. The I50 values of the drugs exhibiting an inhibition effect were found by means of these graphs. It was observed that omeprazole, famotidine, and ranitidine showed inhibition of bovine stomach CA activity. In addition, in vivo studies were performed for these medical drugs in Sprague-Dawley rats. It was demonstrated that CA in erythrocytes was significantly inhibited by these drugs to 3 h. © 2004 Pharmaceutical Society of Japan.