Red Blood Cell Li + - Na + Countertransport , Na + - K + Cotransport

Red blood cell Li-Na countertransport and Na-K cotransport activities, home blood pressure, invasive systemic hemodynamics, and limb venous compliance were measured in 65 white men (23 normotensive, 22 borderline hypertensive, and 20 mild essential hypertensive subjects). Li-Na countertransport activity was positively and significantly correlated with subject-determined home systolic blood pressure (r = 0.31, p < 0.02) and with directly measured systolic (r = 0.29, p<0.02) and diastolic (r=0.27, p<0.03) blood pressures in the hemodynamic laboratory, independent of potential confounding variables. Analysis of the hemodynamic determinants of blood pressure revealed a significant positive correlation of countertransport with vascular resistance (r=0.30, p<0.02) but not with cardiac output or cardiac index. High red blood cell Na-K cotransport activity was not independently associated with hypertension or with a characteristic hemodynamic pattern but was related to decreased venous compliance. Red blood cell Li + -Na + countertransport deserves further study as a marker for the genetic substrate of human essential hypertension. Red cell Na-K cotransport may be altered secondarily by factors related to high blood pressure and seems to be a valid marker for abnormalities of the venous system in hypertension. (Hypertension 9: 459-466, 1987)