Decreased magnesium concentrations of erythrocyte membranes in essential hypertensives

The concentration of magnesium was determined in the plasma, in the cytosol of lymphocytes and platelets and in the cell membranes of erythrocytes in is normotensive subjects and in 19 patients with essential hypertension, pl asma magnesium concentrations were measured by atomic absorption spectrosco py, free magnesium of the cytosol was determined by photometry using the fl uorescence indicator mag-fura-2. Membrane magnesium was measured by atomic absorption spectroscopy, too, and was referred to the membrane protein cont ent, which was measured according to Bradford's method. plasma magnesium co ncentration was 0.92 +/- 0.07 mmol/l in controls versus 0.88 +/- 0.07 mmol/ l in hypertensive patients. Free intracellular magnesium content of lymphoc ytes was 0.38 +/- 0.17 mmol/l in healthy persons and 0.30 +/- 0.16 mmol/l i n patients. Free cytosolic magnesium content of platelets was 0.52 +/- 0.23 mmol/l in control subjects and 0.47 +/- 0.17 mmol/l in hypertensive subjec ts. In the group of hypertensive patients membrane magnesium concentrations were significantly lower than compared with the control persons (0.28 +/- 0.05 versus 0.52 +/- 0.15 mmol/g membrane protein, mean +/- SD, p < 0.001). The magnesium values showed a higher variation in the hypertensive group t han in the normotensive group. Thus, lowered magnesium concentrations may b e involved in the pathogenesis of primary hypertension only in a subgroup o f patients with essential hypertension.