Decreased cellular Mg²⁺ concentrations in a subgroup of hypertensives – cell models for the pathogenesis of primary hypertension

Abstract

A new method to determine total Mg²⁺ content in lymphocytes was developed, offering advantages for routine measurements as compared to fluorescence methods. Intracellular Mg²⁺ measurements were performed in lymphocytes of 18 untreated normotensive and 19 untreated essential hypertensive patients. Mg²⁺ content was referred to lymphocytic protein, which was determined according to Bradford’s method. Mg²⁺ measurements were performed by atomic absorption spectroscopy using a Video 12 apparatus from Thermo Electron Instrumentation Laboratory, Andover, MA, USA. The results show that in patients with essential hypertension, total intralymphocytic Mg²⁺ 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 mg²⁺ content was measured in lymphocytes by the fluorescent indicator mag-fura-II, showing no significant difference in normotensives and hypertensives (0.30 ± 0.16 vs 0.38 ± 0.17 mmol/l). In platelets free intracellular Mg²⁺ concentrations were not found of significant difference in normotensive and hypertensive patients (0.52 ± 0.23 vs 0.47 ± 0.27 mmol/l) using mag-fura-II. In plasma Mg²⁺ concentrations there was no significant difference in the normotensive and hypertensive group (0.92 ± 0.07 vs 0.88 to 0.07 mmol/l). There was no correlation between plasma, free or total cellular magnesium concentrations in each group. Furthermore this method also seems suitable for routine measurements of total intracellular Mg²⁺ concentrations in even larger groups of patients in comparison with fluorescent indicator measurements like mag-fura-II. Lowered total intracellular Mg²⁺ concentrations in a subgroup of primary hypertension may contribute to the development of this disorder, perhaps due to different buffering systems.