FREE PLASMA MAGNESIUM FOLLOWING GLUCOSE LOADING IN HEALTHY HUMANS

The recognized existence of a circadian pattern in extracellular magne sium balance might mirror ei ther an inherent rhythm in the homeostasi s of this ion or dietary factors. Since in vitro insulin enhances cell ular magnesium uptake, the circadian rhythm in extracellular magnesium metabolism might be modulated at least in part by carbohydrate intake . To assess this hypothesis, the effects of oral glucose loading on pl asma total and ionized magnesium were investigted in lean healthy huma ns with a negative family history for essential hypertension and diabe tes mellitus. Plasma total and ionized magnesium was similar before gl ucose loading and 30, 60, 90, 180, and 210 min thereafter. It is there fore concluded that in healthy humans the circadian pattern of extrace llular magnesium is not modulated by the metabolic and hormonal mechan isms that adjust the concentration of glucose.