Regulation of Protein Biosynthesis in Mouse Kidney by Androgens1

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Abstract
The activity of the amino acid activating enzymes of mouse kidney changed in direct proportion with the changes in weight after 3–90 days of castration and 7–28 days of testosterone propionate administration. Furthermore, no changes in the specific activities of these enzymes were revealed by altering the pH (5.5–8.5) of the reaction mixture, or with individual amino acids or various mixtures of amino acids as substrate. On the other hand, the rate of incorporation of leucine-1-C14 into protein of the Si2,Ooo g fraction of the kidney homogenates was greatly decreased after castration and markedly accelerated by testosterone propionate administration. The increase was progressive during the period of stimulated growth of the kidney to a maximum of 900% after 21 days, which coincided with the stimulation of maximal increase in kidney weight. As the kidney was maintained at maximal weight with continued administration of testosterone propionate, the rate of amino acid incorporation showed a small progressive regression. An increased rate of incorporation also was observed for lysine, valine, alanine, glutamic acid, phenylalanine and glycine. Androstan-17β-ol,3-one produced a stimulatory effect on amino acid incorporation similar to that of testosterone propionate. The site of action of the androgens was the microsomal material which also showed an increase in RNA concentration. The amino acid incorporating system was very sensitive to puromycin but not to chloramphenicol.