INTRALYMPHOCYTE FREE MAGNESIUM AND CALCIUM AND INSULIN TOLERANCE-TESTIN A GROUP OF ESSENTIAL HYPERTENSIVE PATIENTS

To ascertain the claimed links between peripheral insulin resistance a nd intracellular magnesium and calcium concentrations, we measured fre e intralymphocyte magnesium (Mg-i) and calcium (Ca-i) concentrations, as well as the rate constant of plasma glucose disappearance (K-itt) a fter insulin injection (insulin tolerance test : ITT), in a group of 1 5 normotensive control subjects (NC) and 29 essential hypertensive sub jects (EH). Mg-i and Ca-i were measured in triplicate by means of a fl uorimetric technique based on the dyes furaptra and fura-2 respectivel y. K-itt value were significantly reduced in hypertensive subjects as compared to control subjects (M +/- SD, EH : 4.54 +/- 1.31 vs 5.63 +/- 1.07; p < 0.02; 95 % confidence limits : 0.22-1.96). Mg-i and Ca-i we re not statistically different in hypertensive subjects as compared to control subjects (Mg-i, NC : 0.274 +/- 0.02 mmol/L; EH : 0.248 +/- 0. 05 mmol/L; Ca-i, NC: 47.6 +/- 9 mmol/L, EH : 46.7 +/- : 13.6 mmol/L). A statistically significant inverse correlation was found in the whole study group between K-itt and body mass index (R = -0.394, p = 0.01) and a statistically significant positive correlation between K-itt and M-gi (R = 0.386; p = 0.012). The latter correlation was no longer sta tistically significant if adjusted for body mass index. Our data are i n favour of a link between index of peripheral insulin resistance and body mass index. A dependance from M-gi is possible but the study lack so far the statistical power to demonstrate it.