EFFECT OF A LONG-TERM HIGH MAGNESIUM INTAKE ON METABOLISM OF ZINC IN SPRAGUE DAWLEY MALE-RATS

The effect of high magnesium intake on the metabolism of zinc was examined in Sprague Dawley male rats. Magnesium was administered for 5 weeks with a standard diet in the form of 1% MgO. Metabolic studies were carried out at 2 and 5 weeks of treatment. High magnesium intake increased magnesemia and urinary and fecal excretion of magnesium. Zincemia was increased after 5 weeks in rats fed a magnesium-enriched diet (32.6 +/- 0.4 vs 29.0 +/- 0.4-mu-mol/l, p < 0.001). Urinary excretion of zinc was decreased after 2 weeks (0.036 +/- 0.003 vs 0.084 +/- 0.009-mu-mol/24h/100 g, p < 0.001), fecal excretion of zinc was also decreased at 2 weeks (1.95 +/- 0.2 vs 4.28 +/- 0.3-mu-mol/24h/100, p < 0.001) and at 5 weeks (1.91 +/- 0.20 vs 3.62 +/- 0.2-mu-mol/24h/100 g, p < 0.001) in rats fed a magnesium enriched diet. Balance and intestinale utilization of zinc were increased by high magnesium intake after 5 weeks (p < 0.001). These findings suggest that oral high magnesium intake can alter metabolism of zinc. The long-term administration of magnesium can facilitate the retention of zinc in Sprague Dawley rats.