Magnesium metabolism in rabbits using Mg28 as a tracer

Abstract

Tracer doses of Mg28 were used to study the metabolism of parenterally administered magnesium. Plasma clearance was rapid, and accumulation of radioactivity in bone started within 2 hours. Of the tissues studied, skin and muscle showed the lowest concentrations of Mg28. In most tissues the ratio of tissue to serum radioactivity became fairly constant after 18 hours. The values for the exchangeable body pool of magnesium, calculated from the specific activities of urine specimens obtained between 18 and 24 hours, approximated the carcass content of magnesium. During starvation the renal excretion of endogenous magnesium amounted to 61.7 mEq/kg of weight loss.