INTRALYMPHOCYTE FREE MAGNESIUM IN A GROUP OF SUBJECTS WITH ESSENTIAL-HYPERTENSION

Despite the importance of magnesium in essential hypertension, few dat a are available on the ionized intracellular concentration of this ion . We therefore studied intralymphocyte free intracellular magnesium (M g-i) in 32 untreated essential hy hypertensive subjects and 27 normote nsive control subjects by means of a fluorimetric technique based on t he use of the new magnesium-sensitive dye furaptra. We also measured i ntralymphocyte ionized calcium (Ca-i) with fura 2. No statistically si gnificant differences were found in Mg-i in hypertensive compared with normotensive subjects (essential hypertensive, 0.291 +/- 0.053 mmol/L ; normotensive, 0.293 +/- 0.043 [mean +/- SD]). A statistically signif icant inverse correlation was established between Mg-i and plasma trig lycerides in essential hypertensive subjects (r = -.521, P = .002). Th e hypertensive group was arbitrarily divided into two subgroups accord ing to plasma triglyceride levels (> 2 [n = 10] or < 2 mmol/L [n = 22] ), and Mg-i proved to be significantly lower in the subgroup with high plasma triglyceride levels compared with either the subgroup with nor mal triglycerides (P = .009; 95% confidence interval, 0.013-0.088) or the nor normotensive control group as a whole (P = .03; 95% confidence interval, 0.003-0.069) (high-triglyceride hypertensive subgroup, Mg-i = 0.256 +/- 0.045 mmol/L; normal-triglyceride hypertensive subgroup, Mg-i = 0.307 +/- 0.049). No statistically significant differences were found in Ca-i in hypertensive compared with normotensive subjects (hy pertensive, 53 +/- 12 nmol/L; normotensive, 54 +/- 14). We did not fin d statistically significant correlations between Ca-i and plasma trigl ycerides, nor did we find any differences in Ca-i between the subgroup of hypertensive subjects with high plasma triglyceride levels and eit her the subgroup of hypertensive subjects with normal triglycerides or the normotensive control group as a whole. The discrepancies between our results in lymphocytes and data relating to either erythrocytes or platelets emphasize the need for caution before the results are extra polated from one tissue to the other. The decreased Mg-i levels in the subgroup of high-triglyceride hypertensive subjects may suggest a rol e for magnesium in plurimetabolic syndrome.