Sex and race differences in sodium-litiihjm countertransport and red cell sodium concentration

A total of 417 Individuals from all four major sex-race groups were examined for the rate of sodium flux via the countertransport pathway and the sodium concentration within red cells. The age span was from early adolescence to retirement. Males of both races had sizably higher countertransport rates than did women (p < 0.01), and a slight increase in sodium concentration (p > 0.05). Contrariwise, white whites of both sexes had higher countertransport than their black counterparts, sodium concentration was higher in blacks than whites (p < 0.01). This pattern is not consistent with a direct relationship between both countertransport or sodium concentratIon and blood pressure which ap plies across both racial groups. Sex-race differences must be taken into ac count in any group comparisons of these variables.