Relation of Calcium and Phosphorus of Diet to Toxicity of Viosterol.

On the Actions of Crystalline Vitamin D2 (Calciferol) in Chronic Parathyroid Tetany1

“…That toxic manifestations may occur without pathological calcifications has been demonstrated by Shelling (32) and others (25). The arterial calcifications seen in experimental hypervitaminosis D do not appear to be related to the arteriosclerosis of man, but represent a deposition of calcium limited to the media, similar to that seen in M6nckeberg's sclerosis (8).…”

“…Toxicity of vitamin D.-Excessive doses of irradiated ergosterol have been shown to be toxic for man (35) and experimental animals (6,8,25). Shohl,Goldblatt,and Brown (16) found that rats fed 4 mgm.…”

“…The toxicity of vitamin D is dependent, at least in part,-on the diet and renal function (8,39). High phosphorus intake and renal impairment, which result in phosphate retention, predispose to greater metastatic calcification.…”

“…A number of factors including dosage (6,7), and calciumphosphorus content of the diet (8), have been found to influence its effect, and where these have not been taken into consideration vitamin D has failed (9,10). The possibility of toxicity and the point made by Shelling and his associates that it raises the serum inorganic phosphorus, has led some workers to question the advisability of using vitamin D in tetany (11,12).…”

Abnormalities of Calcium Metabolism

“…The amounts of viosterol given were suggested by success in the treatment of intractable rickets with large doses 25 and by some of the experimental work of Shelling, in which small doses of vitamin D caused poor calcification of bone ; larger doses, hypercalcification, and still larger doses, décalcification. 26 We might now hesitate to give these amounts.27 A physician of this com¬ munity died, with polyuria, weakness and anorexia, after taking 2,500,000 U. S. P. units daily for seventeen days.28…”