Testosterone regulates the synthesis of major proteins in rat ventral prostate

Abstract

The presence of three major proteins α, β and γ in rat ventral prostate was demonstrated by electrophoresis in polyacrylamide gels containing sodium dodecyl sulphate. Their regulation by androgens was studied by measuring the rates of synthesis of the proteins in minced prostatic tissue by using [35S]methionine. The three proteins account for 30-40% of the proteins synthesized in the gland. After castration, their rates of synthesis rapidly decline to about 1% that of normal animals, and this cannot be accounted for by the accompanying decrease in general protein synthesis. Testosterone reverses these changes in castrated animals, so that after 4 days normal synthesis is restored. The regulation is specific for androgens, since cyproterone acetate, an anti-androgen, is inhibitory and oestradiol-17β and corticosterone are without effect. Preliminary characterization of the proteins indicates that protein α (mol.wt. 22000, pI unknown) is a glycoprotein containing glucose and/or mannose residues and occurs in both the mitochondrial and cytosol fractions. Protein β (mol.wt. 12000, pI5.4) is also a glycoprotein, but is found exclusively in the cytosol fraction. Protein γ (mol.wt.8000, pI5.4) is also found exclusively in the cytosol fraction.