We studied the binding properties of [ 3 H]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 [ 3 H]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. In addition, race had a strong effect on the binding affinity of ouabain to human erythrocytes, with blacks having lower affinities than whites. Because the black population has a much higher prevalence of hypertension than the white population and black women have the highest prevalence of hypertension, this decrease in the affinity of ouabain-binding to the erythrocyte sodium pump molecule may be a possible predictor of adult hypertension. (Hypertension 1990;15:146- Parts of this study were presented at the 60th Scientific Sessions of the American Heart Association in Anaheim, California, November 16-19, 1987. Supported by research grants HL-35788 and HL-32270 from the National Institutes of Health and a Grant-in-Aid from the American Heart Association, Tennessee Affiliate.Address for correspondence: Dr. Emel Songu-Mize, Department of Pharmacology, University of Tennessee, Memphis, 874 Union Ave., Rm 100, Memphis, TN 38163.Received September 20,1988; accepted in revised form October 13, 1989. transport pathways in other tissues, such as the vasculature, have also been noted in some animal models of hypertension.
13- 16 In some reports, normotensive offspring of hypertensive individuals manifested some of these sodium transport abnormalities.
-1718 In spite of extensive knowledge related to cation transport in hypertensive persons, findings related to ouabain-sensitive or the sodium pumpdriven transport system are less definitive than findings for other transport systems. Moreover, binding prop...