NONLINEAR RELATIONSHIP BETWEEN ERYTHROCYTE SODIUM-LITHIUM COUNTERTRANSPORT AND BLOOD-PRESSURE IN MAN

A relationship between erythrocyte Na+/Li+-countertransport activity a nd blood pressure was studied in a randomly selected sample (95 subjec ts) with full range of blood blood pressure, from a representative gro up of inhabitants of one of Moscow's districts. The mean rate of eryth rocyte Na+/Li+-countertransport activity was higher (p <0.01 or less) in the groups of subjects with both borderline (BH) and moderate essen tial hypertension (EH) as compared with the group of normotensives (NT ). A positive correlation was found between the erythrocyte Na+/Li+-co untertransport rate and age and body weight in the entire selected gro up. The total contribution of these confounding parameters is responsi ble for 20.4% of the interindividual variability of the Na+/Li+-counte rtransport activity. The individ ual Na+/Li+-countertransport values r emained unchanged during at least 2 years of follow-up. A nonlinear re lationship between erythrocyte Na+/Li+-countertransport activity and b lood pressure was established in the entire group. No significant asso ciation between blood pressure and Na+/Li+-countertransport was seen a t high and low values of these two parameters. A pronounced change in the erythrocyte Na+/Li+-countertransport values occurred within a narr ow borderline blood pressure range.