Magnesium release from red blood cells of hypertensive man by the ionophore A 23187.

Free intracellular magnesium in red blood cells (RBC) of 9 normotensives and 7 essential hypertensives was estimated from the amount of magnesium released by an incubation with the ionophore A 23187 (8 microM). In hypertensives, Mg released to the suspension medium was 0.42 +/- 0.10 mmol/l, thus being significantly lower than in normotensives (0.52 +/- 0.09 mmol/l; p less than 0.05). Total RBC Mg and serum Mg were not different in both groups. The chloride distribution ratio between the extracellular and intracellular concentrations was insignificantly increased in hypertensives, thus indicating a depressed intracellular chloride concentration as reported earlier. This ratio is essential for the calculation of the free intracellular Mg from equilibrated extracellular Mg. Taking the latter finding into account, no significant depression of free intracellular Mg can be detected in RBC of hypertensives in this study.