Lowered total intracellular magnesium status in a subgroup of hypertensives

Abstract

A new method to determine total Mg⁺⁺ content in lymphocytes was developed, offering advantages for routine measurements as compared to fluorescence methods. Intracellular total Mg⁺⁺ measurements were performed in lymphocytes of 18 healthy subjects and 19 untreated essential hypertensive patients. Mg⁺⁺ content was referred to lymphocytic and membrane protein, which was determined according to Bradford's method. Mg⁺⁺ measurements were performed by atomic absorption spectroscopy using a Video 12 apparatus of Thermo Electron Instrumentation Laboratory, Andover, USA. The results show that in patients with essential hypertension total intralymphocytic Mg⁺⁺ content is significantly lower (0.07±0.05 mmol/g lymphocytic protein, mean ± s.d.) as compared to controls (0.11±0.04 mmol/g lymphocytic protein, mean ± s.d., p<0.05).

Free intracellular Mg⁺⁺ content was measured in lymphocytes by the fluorescent indicator mag-fura-II, showing no significant differences in normotensives and hypertensives (0.30±0.16 versus 0.38±0.17 mmol/l). Additionally, in platelets free intracellular Mg⁺⁺ concentrations were not found of significant difference in normotensives and hypertensives (0.52±0.23 versus 0.47±0.27 mmol/l) using mag-fura-II. In plasma Mg⁺⁺ concentrations there was no significant difference in the normotensive and hypertensive group (0.92±0.07 versus 0.88±0.07 mmol/l). There was no correlation between plasma or free or total cellular magnesium concentrations in both groups. Furthermore this method seems also suitable for routine measurements of total intracellular Mg⁺⁺ concentrations in even larger measurements like mag-fur-II. Lowered total intracellular Mg⁺⁺ concentrations in a subgroup of primary hypertensives may contribute to the development of this disorder, perhaps due to different buffering systems.