The Hypomagnesemia of Vitamin D Administration.

Abstract

Summary The hypomagnesemia consequent to administration of large doses of vit D₂ to rats was studied. Two groups of animals were pair-fed a magnesium-deficient diet, and one was then given injections of vit D_2. Hypomagnesemia resulted in the vit D₂-treated group. During the period of vitamin administration there was no significant difference between the urinary or fecal magnesium excretion of the 2 groups. Nor were the differences significant between the levels of magnesium in the total carcass and muscle. The level of serum proteins also was not different in the 2 groups. It is suggested that the hypomagnesemia is due to a redistribution of magnesium from the extracellular phase to some other depot, which may well be bone. One mechanism might involve a reduced binding of magnesium by serum proteins due to some specific effect of vit D₂ (or perhaps to the resultant hypercalcemia). An alternative hypothesis is that vit D₂ has some other specific influence that promotes a deposition of magnesium in bone or some other depot.