Subacute Toxicity of Radioactive Phosphorus as Related to the Composition of the Diet ∗

Abstract

Summary

In mice on a 10% casein, 32% fat diet, the LD₅₀ dose at the 21st day lies between 4 and 6 microcuries per g of body weight. Neither the fatty infiltration of the liver (induced by a deficiency of lipotropic factors, with or without partial poisoning with OCl₄), or its prevention (by supplementing the diet with choline) changes the survival figures. The time of 50% deaths, the percentage of survivors at the 21st day and the average survival time of mice injected with P³² are highest with a diet low in fat and in protein, and are significantly decreased when the level of the fat, or of the protein, or both, are increased in the diet. Enrichment of the diets with inorganic phosphate seems to afford a moderate, but significant degree of protection against the injurious action of P³².