Ouabain-binding and ⁸⁶rubidium-uptake in lymphocytes of normal and borderline hypertensive subjects

Abstract

In borderline hypertensives cellular sodium concentration seems to be increased, indicating that cellular abnormalities are present in the early course of essential hypertension. In order to study the mechanisms underlying this finding the number of sodium/potassium pump sites and the cation pump activity were studied in lymphocytes of nine borderline hypertensives (27 (20–36) years) and nine controls (28 (20–36) years). Maximum ³H-ouabain binding and ⁸⁶Rb-uptake were taken as measures of the number of pump sites and cation pump activity, respectively. The median number of sodium/potassium pump sites was 49.6 × 10³ molecules/cell in the BH group compared to 32.4 × 10³ in the control group (P<0.01). Median 90 min ⁸⁶Rb-uptakes were 54.0 pmol/10⁶ cells in BH subjects and 39.4 in controls (P<0.10). The increased number of sodium/potassium pump sites and the tendency to increased cation pump activity in lymphocytes of BH subjects in vitro may be interpreted as an adaptive change possibly induced by a circulating natriuretic substance.

Key Words:

• borderline hypertension
• ouabain-binding
• ⁸⁶rubidium-uptake