INDUCTION OF SEVERAL ADAPTIVE ENZYMES BY ACTINOMYCIN D.

Although actinomycin D has been used to prevent protein synthesis in experiments of several hours' duration, its effects on the synthesis of adaptive enzymes which are induced over a period of several days have received less attention. Treatment of young rats with doses of actinomycin D, which permitted survival for a period of 5 days, resulted in marked increases in the activities of four hepatic enzymes known to be induced by cortisol: alanine transaminase, tyrosine transaminase, serine dehydrase, and tryptophan pyrrolase. Actinomycin D also induced responses of two of these enzymes in adrenalectomized rats.