[Changes of transmembrane ion transport in essential hypertensives with familial histories]

To investigate the effects of heredity on transmembrane ion transport in essential hypertension (EH).

52 essential hypertensives were divided into two groups, 23 with positive family history (FH(+)) and 29 with negative family history (FH(-)). The rate constant of ouabain-sensitive sodium efflux ((o)K(os)) was measured as the half of the increase in erythrocyte Na(+) concentration during incubation with ouabain for 2 hours, (o)K(os) was calculated by an equation and the maximal rate (Vmax) of red cells Na(+)/H(+) exchange was determined as the Na(+) influx promoted by an outward H(+) gradient. Intracellular Na(+) concentration was measured with flame photometry and (45)Ca(2+) influx in ATP-depleted red cells with liquid scintillation counting.

The red cell Na(+)/H(+) exchange and (45)Ca(2+) in-flux were significantly higher but the (o)K(os) lower in both the FH(+) and FH(-) groups than in the controls. FH(+) group demonstrated a significantly higher (o)K(os) and lower Ca(2+) influx as compared with those in FH(-) group. In FH(+) group, systolic blood pressure was positively correlated with age, while diastolic blood pressure positively correlated with (45)Ca(2+) influx.

Our data show a genetic contribution to abnormal membrane transport in hypertension. There is a defect in membrane permeability to Ca(2+) and a greater exchangeable pool of cytosolic free Ca(2+) in FH(+) group that participate in the pathogenesis of inherited hypertension.