Studies in Inorganic Metabolism

Although considerable data have been gathered on the metabolism of the ash constituents, the literature concerning the interrelations between calcium and magnesium metabolism is very limited. This experiment was undertaken to ascertain whether an increased intake of calcium would affect the urinary and fecal excretion of magnesium and eice r’ersn, thus showing intcrrclations between the metabolism of these two elements. The injection of calcium salts, according to observations of lMenclel and Benedict on dogs, cats, and rabbits cl), was followed by increased elimination of magnesium in the urine and similarly the injection of a magnesium salt increased the output, of urinary calcium (2). Givens (3) found that the ingestion by human subjects of calcium in the form of raw milk, dried milk, or calcium lactate (about 1.5 to 5 gm.) caused an increased urinary calcimli, while the ingestion of magnesium citrate (1 to 2.5 gm.) apparently had no effect on the urinary magnesium. Calcium lactate was less effective than milk in this respect. Underhill, Honeij, and Bogert (4) found that the ingestion of calcium lactate (2 gm.) increased the urinary calcium but not the urinary magnesium, while the same amount of magnesium citrate taken by mouth increased the urinary magnesium but not the urinary calcium. Malcolm (5) has presented cvidcncc to show that ingestion of soluble m.agnesium salts causes a loss of calcium in adult dogs and