Counteraction of Cortisone Inhibition of Body,Hair and Thymus Growth by Vitamin B 12 and Aureomycin. ∗

Abstract

Summary

(1) Cortisone was injected in daily doses of .5 mg for 30 days into 130 immature male albino rats on a vitamin B₁₂-deficient diet. The depressions of body, hair, and thymus growth which resulted were completely or partially prevented by incorporating 200 fig of vit. B₁₂ pr kilo of ration or .005% aureomycin. (2) Vit. B₁₂ was more effective in these respects than aureomycin, and the combination of the two substances was more effective than either alone. (3) The favorable actions of the vitamin and antibiotic were accompanied by an increase in food consumption and greater efficiency in converting food into body weight gains. (4) It is concluded that when large doses of cortisone are injected into rats on a vit. B₁₂-deficient diet, the deficiency becomes aggravated and thus accounts at least in part for the observed inhibitions of body and hair growth. The mechanisms by which vit. B₁₂ and aureomycin protect the thymus against cortisone action are as yet unknown.