ABNORMAL RED-CELL SODIUM CONTENT AND EFFLUX IN JAPANESE PATIENTS WITH ESSENTIAL-HYPERTENSION

Net Na efflux and K influx were determined in Na-loaded/K-depleted erythrocytes derived from 37 patients with essential hypertension and 25 age-matched normotensive subjects with no family history of hypertension, together with the measurement of basal red cell Na and K contents. Intraerythrocyte Na content was significantly higher in the essential hypertensives than in the normotensives (10.9 .+-. 1.4 vs. 10.0 .+-. 1.2 mmol l .cntdot. cell, mean .+-. SD, P < 0.02) but K content was nearly equal between the 2 groups. Net Na efflux in the hypertensives was significantly reduced compared with that in the normotensives (4.57 .+-. 0.70 vs. 5.18 .+-. 1.02 mmol l .cntdot. cell .cntdot. h, P < 0.01), but both net K influx and net Na/K flux ratio were not significantly different between the 2 groups. Net Na efflux and K influx showed a significant inverse correlation with red cell Na content (r = -0.64 and r = -0.56, respectively, P < 0.001). The reduced net Na efflux with the increase of red cell Na content may be related to the pathogenesis of essential hypertension. It is impossible to determine the genetic marker of essential hypertension by using the net Na/K flux ratio of Japanese subjects, although Garay et al. reported that this index was abnormally low in the case of Europeans.