Ouabain-resistant, frusemide-sensitive sodium efflux in human lymphocytes: a comparison of normotensive and hypertensive subjects.

Peripheral blood lymphocytes were isolated at room temperature in a low sodium medium in 17 normotensive control subjects (NC) and 13 patients with essential hypertension (EHP). Lymphocyte sodium content was not significantly different between NC and EHP (3.1 +/- 0.5, n = 11, and 3.6 +/- 0.5, n = 10, respectively; means +/- SEM). The effect of frusemide on the ouabain-resistant rate constant of sodium efflux (KNao) from these lymphocytes into a sodium-free medium was measured. The frusemide-sensitive efflux rate constant was 75 +/- mus (n = 17) in controls and significantly lower in EHP (32 +/- 7 mus, n = 13, P less than 0.001). In human lymphocytes there is a ouabain-resistant, frusemide-sensitive fraction of sodium efflux into a sodium-free medium; this fraction may be reasonably attributed to a sodium-potassium cotransport system. This sodium transport pathway seems to be reduced in lymphocytes from EHP.