Decreased Platelet Free Magnesium with Increased Free Calcium in Mild Essential Hypertension.

Abstract

Intracellular free magnesium and calcium concentrations of platelets from 21 mild essential hypertensive patients and 8 normotensive individuals were measured using mag-fura2, a recently developed fluorescent indicator, and fura2, respectively. Compared with normotensives, intracellular free magnesium concentration was significantly decreased (0.32±0.10 vs. 0.50±0.15mmol/l, mean±SD, p<0.001) and intracellular free calcium concentration was significantly increased (40.2±9.0 vs. 21.7±11.8 nmol/l, p<0.001) in the hypertensives. In all subjects, mean blood pressure correlated negatively with intracellular free magnesium (r=-0.57, p<0.001) and positively with intracellular free calcium (r=0.48, p<0.02). Furthermore, intracellular free magnesium correlated negatively with intracellular free calcium. In contrast, serum and intraerythrocyte magnesium concentrations did not differ between the two groups. These results suggest that the decreased intracellular free magnesium of platelets concomitant with the increased intracellular free calcium may participate in the pathophysiology of essential hypertension. (Hypertens Res 1992; 15: 105-110)