Effects of primycin on the synthesis of tryptophan pyrrolase

Abstract 1. In the liver of adrenalectomized rats a subtoxic dose of primycin inhibits the synthesis of tryptophan pyrrolase induced by hydrocortisone. 2. Primycin does not substantially affect the enhancement of the activity of TP observed in the liver of adrenalectromized animals after administration of 1-tryptophan. 3. The above effects of primycin are similar to those of actinomycin-D.