Influence of magnesium supplementation on parathyroid hormone and bone Gla protein concentration in normal rats

Adult male rats were used to study the in vivo effects of hypermagnesemia on parathyroid hormone (PTH) and bone Gla protein (BGP) plasma concentrations. Rats were given an Mg-supplemented diet at three different Mg levels (0.40, 0.60 and 0.80%). Results were compared to those obtained in control rats fed a standard diet containing 0.21% of Mg. A significant decrease in PTH plasma levels with no change in total calcium and phosphorus was observed in rats fed the 0.60 and the 0.80% Mg diet. No change of BGP was observed at any level of Mg in the diet. These results suggest that mild hypermagnesemia obtained by dietary Mg supplementation has no apparent effects on both production and binding of BGP to hydroxyapatite.