Effects of magnesium, sodium, calcium or potassium intakes on magnesium content in rat skeletal muscle.

Magnesium skeletal (myocardium and gastrocnemius) content has been studied in rats supplemented with 30 mM dissolutions of Mg2+, Na+, Ca2+ and K+ in drinking water, for 7 or 30 days. In both muscles, the ingestion of Mg2+ for 30 days increased Mg2+ content, while Ca2+ and K+ supplementation caused a significant drop. The increase in Na+ ingestion reduced Mg2+ content in gastrocnemius. There were no significant differences between control and animals supplemented for 7 days. These results suggest that, in the case of supplementation situations, the control mechanisms of the Mg2+ tissular content have a lower gain than those of Na+ and K+ of one order of magnitude.