INTRACELLULAR AND EXTRACELLULAR MAGNESIUM DEPLETION IN TYPE-2 (NON-INSULIN-DEPENDENT) DIABETES-MELLITUS

To investigate alterations of magnesium metabolism in Type 2 (non-insu lin-dependent) diabetes mellitus, we utilized a new magnesium-specific selective ion electrode apparatus to measure serum ionized magnesium (Mg-io) in fasting subjects with and without Type 2 diabetes, and comp ared these values to levels of serum total magnesium, and of intracell ular free magnesium (Mgi) analysed by P-31-NMR spectroscopy. Both Mg-i o (0.630 +/- 0.008 vs 0.552 +/-0.008 mmol/l, p < 0.001) and Mgi (223.3 +/- 8.3 vs 184 +/-13.7 mmol/l,p < 0.001), but not serum total magnesi um, were significantly reduced in Type 2 diabetes compared with nondia betic control subjects. Furthermore, a close relationship was observed between serum Mg-io and Mgi (r = 0.728, p < 0.001). We suggest that m agnesium deficiency, both extracellular and intracellular, is a charac teristic of chronic stable mild Type 2 diabetes, and as such, may pred ispose to the excess cardiovascular morbidity of the diabetic state. F urthermore, by more adequately reflecting cellular magnesium metabolis m than total serum magnesium levels, Mg-io measurements may provide a more readily available tool than has heretofore been available to anal yse magnesium metabolism in a variety of diseases.