Maximum binding of ouabain to erythrocytes in relation to a family history of essential hypertension, sodium balance and body weight in normotensive children.

The number of sodium pump receptors in erythrocytes (maximum binding of ouabain to erythrocytes; Bmax) was examined in relation to a family history of essential hypertension (FH-HT), the body mass index (BMI), urinary sodium excretion and blood pressure in 71 normotensive children (13 to 15 years of age), and in relation to sodium intake in 6 children who had various kidney diseases but displayed a normal renal function (6 to 13 years of age). Bmax was significantly lower in children with FH-HT than in those without FH-HT. However, the BMI, urinary sodium excretion and blood pressure showed no significant differences between the groups. Bmax was not significantly different between the top 20% tile group of BMI or urinary sodium excretion and the bottom 20% tile group of BMI or urinary sodium excretion. Furthermore, Bmax was unchanged during and after restriction of sodium intake in children with nephropathy. These findings suggest that Bmax may be a genetic marker for essential hypertension, since it was suppressed regardless of the BMI or urinary sodium excretion in normotensive children with FH-HT, and since it did not change according to sodium intake in children with renal diseases.