Methods and findings in experimental and clinical pharmacology vol:19 issue:2 pages:125-8
The effect of the angiotensin-converting enzyme inhibitor, captopril, on Na+/H(+)-exchange activity and on Ca(2+)-ATPase mediated Ca(2+)-efflux was investigated in red blood cell membranes of patients with essential hypertension. The erythrocyte Na+/H(+)-exchange rate was measured as the difference in H(+)-efflux rate when measured in the presence or absence of Na+. The erythrocyte Ca(2+)-transport mediated by Ca(2+)-ATPase was assayed as the erythrocyte Ca(2+)-efflux rate. Our data show that captopril, in vitro and in vivo, inhibits the Ca(2+)-ATPase mediated Ca(2+)-efflux rate in human erythrocytes, while in vivo it stimulates the erythrocytes Na+/H(+)-exchange rate.