[Cation flux in erythrocytes of patients with essential hypertension]

86Rubidium influx and Na--K-cotransport have been investigated in erythrocytes of mild essential hypertensives and normotensives devoid of familial hypertension. For measurement of cotransport Na-loaded/K-depleted erythrocytes were used while rubidium influx (with and without ouabain) was determined under physiological conditions. Both transport systems were linear in time, the interassay variances in a range of about 10%. The patients with essential hypertension exhibited a decreased rubidium influx compared to the normotensive controls. Ouabain-sensitive fluxes were not significantly different between the two groups, whereas ouabain-resistent rubidium influx was diminished in the group of the patients. Na--K-cotransport was also found to be decreased in essential hypertension. There was no correlation between cotransport and Rb-influx. The results indicate changes in cation fluxes in erythrocytes of essential hypertensives, the Na--K-cotransport being rather more altered than rubidium influx. It is speculated that hypertensive persons with reduced rubidium flux rates may represent a subpopulation of essential hypertension and that their high blood pressure may be additionally influenced by exogeneous factors e.g. enhanced sodium uptake.