Correlation between magnesium and potassium contents in muscle: role of Na+-K+ pump

Magnesium depletion is accompanied by potassium loss in ratsoleus and extensor digitorum muscles as determined by magnesium depletion experiments in vivo and in vitro. Intracellular and extracellular magnesium depletion did not affect the activity of the sodium-potassium pump as proven byouabain blocking experiments. Rather, magnesium depletion was coupled with the elevation of potassium extrusion by as much as 42% of normal.