Distribution of an Unidentified Antithyrotoxic Factor in Materials of Plant and Animal Origin.

Abstract

Growth was markedly reduced in hyperthyroid rats fed a purified ration containing casein as the dietary protein and sucrose as the dietary carbohydrate. The retardation in growth was completely counteracted by the admn. of a water-insoluble fraction of liver, desiccated and defatted kidney and a fermentation product derived from cultures of Streptomyces aureofaciens. Full fat soybean flour also showed considerable activity. Crystalline aureomycin HC1 was inactive. Other materials of plant and animal origin showed little if any activity. The protective factor was apparently distinct from any of the known nutrients.