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, plasma magnesium concentrations were measured by atomic absorption spectroscopy, free magnesium of the cytosol was determined by photometry using the fluorescence indicator mag-fura-2. Membrane magnesium was measured by atomic absorption spectroscopy, too, and was referred to the membrane protein content, which was measured according to Bradford's method. plasma magnesium concentration was 0.92 +/- 0.07 mmol/l in controls versus 0.88 +/- 0.07 mmol/l in hypertensive patients. Free intracellular magnesium content of lymphocytes was 0.38 +/- 0.17 mmol/l in healthy persons and 0.30 +/- 0.16 mmol/l in 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 subjects. 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 than in the normotensive group. Thus, lowered magnesium concentrations may be involved in the pathogenesis of primary hypertension only in a subgroup of patients with essential hypertension.