9 research outputs found
Free plasma magnesium following glucose loading in healthy humans
The recognized existence of a circadian pattern in extracellular magnesium balance might mirror either an inherent rhythm in the homeostasis of this ion or dietary factors. Since in vitro insulin enhances cellular 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 plasma total and ionized magnesium were investigated in lean healthy humans with a negative family history for essential hypertension and diabetes mellitus. Plasma total and ionized magnesium was similar before glucose loading and 30, 60, 90, 180, and 210 min thereafter. It is therefore concluded that in healthy humans the circadian pattern of extracellular magnesium is not modulated by the metabolic and hormonal mechanisms that adjust the concentration of glucose
Free circulating magnesium and renal magnesium handling during acute metabolic acidosis in humans
Ion-selective electrodes have been designed for determining the ionized concentration of magnesium in blood, the biologically active form of this ion. The effect of acute acidosis induced by ammonium loading on circulating and urinary magnesium was investigated in 11 volunteers. No changes in plasma total and ionized magnesium were noted following administration of ammonium chloride. On the contrary, administration of ammonium chloride increased the plasma free magnesium fraction and the urinary magnesium excretion. The study demonstrates that the hypermagnesiuria induced by acute acidosis is not caused by ionized hypermagnesemia and supports the theory that acidosis decreases the circulating magnesium fraction that is bound to proteins