Lability of the protein biosynthesis system of the mouse kidney and its relationship to the regulatory effect of androgens.

Abstract

ABSTRACT The amino acid (leucine, phenylalanine) incorporation system of the postmitochondrial fraction (S2) from the kidney of normal, castrated and testosterone propionate treated mice lost all of its activity on storage over-night at 5°C. The loss in activity was evident within one hour of storage at 4°C. Most of the amino acid incorporating activity was lost within 10 min on preincubation at 37°C. Addition of polyuridylic acid was not able to restore the activity. Neither castration nor the administration of androgen influenced the rate of loss of the amino acid incorporating activity. Separation of the soluble (S3) and microsomal (Ms) fractions and preincubation of either of the fractions produced loss in activity. The addition of poly U restored the activity of the preincubated Ms but not the preincubated S3 fraction. Storage of S2 at −20°C only retarded the rate of loss in activity. The addition of poly U to the enzyme system restored all of the phenylalanine incorporation activity for the castrated mice and most but not all of that of the androgen treated mice. The loss in activity was not accompanied by any detectable change in the RNA.