SPIRONOLACTONE PREVENTS NA+ H+ EXCHANGE ENHANCEMENT IN PRIMARY ALDOSTERONISM/

The study was undertaken to determine the possible effect of an aldost erone antagonist, spironolactone (SP), on red blood cell sodium-hydrog en exchange (NHE) enhancement in primary aldosteronism (PA) and essent ial hypertension (EH). NHE was measured as the amiloride-inhibited fra ction of H+ efflux (V-max) from erythrocytes (pH(i) 6.40 +/- 0.05) int o a Na+-containing medium (pH(o) 8.00 + 0.05). Subjects were 12 hypert ensive patients with aldosterone-producing adrenal adenoma (six treate d with 200 mg/day spironolactone for an least 5 days and six drug-free ), 20 essential hypertensives (10 treated with the same regimen of spi ronolactone and 10 drug-free), and 20 healthy controls. Treatment with spironolactone decreased NHE in PA patients but did not change the me an NHE in essential hypertensives. It is concluded that SP may be usef ul to differentiate between elevated NHE in PA and essential hypertens ion. (C) 1997 American Journal of Hypertension, Ltd.