A new test showing abnormal net Na+ and K+ fluxes in erythrocytes of essential hypertensive patients.

A new and simple laboratory test for measuring net Na+ and K+ fluxes in Na+-loaded/K+-depleted human erythrocytes was developed and applied to hypertension. Moderate essential hypertension (10 patients) was characterised by a constant increase in net K+ influx, possibly related to higher Na+, K+-pump activity. In more severe cases (8 patients) net Na+ efflux from erythrocytes dropped. The ratio of Na+/K+ net fluxes was therefore reduced in all essential hypertensive patients. Conversely, Na+ and K+ erythrocyte fluxes were normal in hypertension of renal origin (5 patients). Erythrocyte K+ influx was normal in young normotensive people born of normotensive parents (17 cases), but was increased in 5 of 8 young normotensive people born of essential hypertensive parents, in families where blood-pressure has been recorded for three generations. This result, which seems to indicate genetic transmission, suggests that measurement of Na+ and K+ erythrocyte fluxes may help to detect subjects liable to high blood-pressure.