Hormonal regulation of protein synthesis in rat ventral prostate.

Abstract

To elucidate details of hormonal regulation mechanism in rat ventral prostate, synthesis of RNAs that contain polyadenylate sequences, polyribosomal sedimentation profile, ribosomal capacity of 3H-Met-tRNA binding, ribosomal initiation factor activity and the rate of polypeptide chain elongation were examined in the ventral prostate from control and castrated animals. The following results were obtained; 1) The concentration of RNAs that contain polyadenylate sequences in cytoplasm of castrated rats was markedly decreased, while the content in nuclear fraction was not influenced significantly by castration. 2) Polyribosomes disappeared quite rapidly after castration and were completely restored 48 hr after testosterone administration. 3) Ribosomal binding capacity with 3H-Met-tRNA and ribosomal initiation factor activity were also reduced significantly. Testosterone treatment of castrated animals completely abolished the effect of castration on ribosomal binding capacity with 3H-Met-tRNA and initiation factor activity. 4) A relatively small effect of castration on the relative rate of polypeptide chain elongation in rat ventral prostates was observed. These results may indicate that the regulation of protein synthesis exerted by testosterone in rat ventral prostates is not restricted at the step of the transcription of mRNA.