Race, sex, and family history of hypertension and erythrocyte sodium pump [3H]ouabain binding.

We studied the binding properties of [3H]ouabain to erythrocytes from normotensive children (n = 83) between the ages of 10 and 18 years (mean resting arterial pressure: 102/57 mm Hg) from normotensive and essential hypertensive parents. Arterial blood pressures of 101/57 and 104/57 mm Hg (subjects with normotensive and hypertensive parents, respectively) were not significantly different between the two groups. Forty-four children had normotensive parents and 39 had hypertensive parents, 51 were white and 32 were black, and 41 were girls and 42 were boys. By using the [3H]ouabain-binding technique, we determined the density of sodium pump sites and the equilibrium dissociation constants in erythrocytes from these children. Possible effects of race, sex, or parental hypertension status on pump sites and dissociation constants were tested with a three-way analysis of variance (ANOVA). Race had a major effect on the dissociation constant: blacks had a significantly higher value than did whites (p = 0.002). We also found a race by sex by parental hypertension status interaction (p = 0.04) with black girls with hypertensive parents having the highest value. There was no effect of race, sex, or status on sodium pump site density. Age, height, weight, resting arterial blood pressure, and plasma Na+ and K+ concentrations did not correlate with the dissociation constants. These data suggest that, among the groups we studied, black girls with hypertensive parents had erythrocytes with the lowest binding affinity for ouabain.(ABSTRACT TRUNCATED AT 250 WORDS)