Prevention by Vitamin B 12 of Protein Catabolic Action of Cortisone. ∗

Abstract

Summary

1. Fifty young male rats were divided into 5 uniform groups and were fed a vit. B₁₂-deficient diet for 20 days. For the following 30 days, one group received 200 μg of vit. B₁₂/kilo of diet, another was continued on the deficient diet, and the other 3 groups were injected with large doses of cortisone acetate with or without vit. B_12. 2. Vit. B₁₂ alone did not alter daily urinary nitrogen excretion/100 g body weight, but increased appetite and body weight gains. Without vit. B₁₂, cortisone significantly increased daily urinary nitrogen losses and reduced body growth and food consumption. Vit. B₁₂ largely prevented these protein catabolic actions of cortisone under ad lib. feeding, but was ineffective when food intake was reduced to that of rats given cortisone without vit. B_12. 3. It is concluded that (a) vit. B₁₂ can prevent increased urinary nitrogen losses induced by cortisone, probably by increasing appetite and thereby enhancing the availability of carbohydrate or protein to the organism (b) large doses of cortisone can markedly inhibit the ability of vit. B₁₂ to transform food into body weight gains. Other implications of these findings are discussed.