Physicochemical characterization of the androgen receptor in rat uterine cytosol

In this manuscript a number of physicochemical and DNA-binding properties of the androgen receptor from rat uterus were characterized. The dissociation of [³H] testosterone from the receptor followed first order kinetics, with a half-time dissociation rate of approximately 48 h at 0 C. Maximum binding was maintained at pH 7. Ammonium sulfate precipitated the receptor at concentrations between 25-40% saturation. Gel filtration and sucrose gradient analysis revealed a 62 Å, 6S binding component (mol wt, 167,000; frictional ratio, 1.71) in both the absence and presence of the protease inhibitor leupeptin. Isoelectric focusing revealed an isoelectric point of 5.9. The receptor bound to DEAE-agarose, heparin-Sepharose, and hydroxylapatite. Increased receptor binding to phosphocellulose and DNAcellulose was observed after heat treatment at 24 C for 30 min. These results demonstrate that the uterine androgen receptor has many properties similar to those of androgen receptors in male target tissues.