Influence of low magnesium concentrations in the medium on the antioxidantsystem in cultured human arterial endothelial cells

Using cultured human endothelial cells, we investigated the contribution of concentrations of magnesium to the antioxidant system and oxidative stress . Cells were cultured at decreasing magnesium levels (569, 380, 190 and 95 mu M) for 72 h. We then measured the amount of released hydrogen peroxide ( H2O2) from the cells, the consumption of exogenous H2O2, the intracellular reduced glutathione (GSH) and the oxidized glutathione (GSSG) contents and the activities of glutathione reductase and catalase. Magnesium at a level of 949 mu M was used as a control. The effect of magnesium deficiency on ce llular membrane permeability was determined by measurement of the amount of [C-14] amino acid mixture released from the cells. The results showed that during 72 h of magnesium-deficient treatment, the H2O2 release from the ce lls gradually increased and consumption of exogenous H2O2 was enhanced duri ng the first 48 h of treatment. GSH content gradually decreased but GSSG wa s not affected. The activity of glutathione reductase was first stimulated and then inhibited. Catalase activity was gradually reduced. [C-14]Amino ac id mixture release from the cells continuously increased. We suggest that m agnesium deficiency affected the intracellular antioxidant system in cultur ed endothelial cells.