Some Characteristics of the Steroid-Sensitive Amino Acid Incorporating System of Mouse Kidney

Abstract

The incorporation of glycine, leucine and phenylalanine into cell-free homogenates of mouse kidney was increased 30–70% by pretreatment with testosterone propionate; smaller effects were found with methionine, serine and valine. Hydrocortisone inhibited the incorporation of glycine, leucine, phenylalanine and valine; incorporation of either methionine or serine was not affected. More than 90% of the radioactivity which was incorporated in experiments with glycine and leucine was found in a fraction sedimenting at 900 g. Neither incorporation per se, nor the changes occurring in response to steroid hormones, was dependent upon soluble (900 gsupernatant) factors of the homogenate. Although phenylalanine was incorporated into the 900 g-supernatant fraction as well as into the “nuclear” fraction, only the latter responded to testosterone propionate.