Use of 86 Rb and 22 Na in assaying active and cotransport activities in human erythrocytes in a biracial population

Abstract

A defect in Na +-K + transport across the red cell membrane has been shown to be associated with essential hypertension. A sensitive assay system to measure active, co- and countertransport systems in erythrocytes from normotensive adults was developed. Active, co- and countertransport systems in the erythrocytes were assayed by measuring the influx of radioactive 22Na + and 86Rb +. In the biracial (black-white) population group studied, analysis of variance of the active transport showed a significant race effect ( p = 0.003). Cotransport activity showed age by race interaction ( p = 0.001) and age by sex ( p = 0.02). Cotransport activity was significantly higher in whites than blacks ( p = 0.0001). Countertransport activity did not vary either by sex or race. Of the Spearman correlation coefficients for transport activities and blood pressure, white males showed a strong positive correlation with countertransport, whereas in black males, blood pressures showed a strong interaction with active transport. Among the transport activities, active transport showed significant interaction with countertransport activity in black males, whereas cotransport activity in whites showed a strong interaction with countertransport. The results suggest a subtle difference in Na +-K + transport systems between blacks and whites, and these variations may be related to differences for susceptibility to essential hypertension.