Purification and Characterization of the Androgen Receptor from Rat Ventral Prostate

The androgen receptor has been purified from rat ventral prostate cytosol by a combination of differential DNA-Sepharose 4B chromatography and testosterone 17β-hemisuccinyl-3,3′-diaminodipropylamine-Sepharose 4B affinity chromatography. Approximately 8 µg of protein was obtained from 38 g of rat ventral prostate, with a yield of 24%. The receptor was purified approximately 120000-fold. Silver nitrate staining of a sodium dodecyl sulfate (NaDodSO₄)-polyacrylamide gel revealed a major polypeptide band migrating at 86 000 daltons. Affinity labeling of a partially purified receptor preparation with either 17-hydroxy-17α-[³H]methyl-4,9,11-estratrien-3-one or 17β-hydroxy-[1,2,4,5,6,7,16,17-³H₈]-5α-androstan-3-one 17-(2-bromoacetate) produced a major band of radioactivity migrating at 86 000 daltons on a NaDodSO₄ gel. Under nondenaturing conditions, a M_r of 85 000 was determined by gel filtration (42 Å) and sucrose gradient sedimentation analysis (4.5 S). The purified receptor had an isoelectric point of 6.3. [³H]-4,5α-Dihydrotestosterone, bound to the purified receptor, was displaced with 4,5α-dihydrotestosterone > testosterone ≫ progesterone > 5α-androstane-3α,17β-diol > 17β-estradiol > Cortisol. A number of physicochemical properties of the purified receptor were similar to those of the receptor in crude cytosol.