Evidence of transformed androgen receptor in rat submandibular gland by three-step column chromatography

Abstract

The transformation of cytosolic androgen receptors was studied in the male rat submandibular gland (SMG) at 3 and 7 weeks of age, using 3H-R1881 as the labeled ligand. Sephacryl S-200 column chromatography revealed two R1881 binding proteins having a mol wt of 150-200 kDa and 14-20 kDa in cytosol. The affinity column of DE52 cellulose gave the main peak of cytosolic receptor at the KCl concentration of 1.5-2.5 M, demonstrating that the association of the 150-200 kDa with 14-20 kDa forms would depend on the ionic environment. The cytosolic 150-200 kDa protein, which had a high specificity to androgen, became lower in molecular weight to 14-20 kDa following DE52 cellulose column chromatography. The nuclear KCl extracted receptor, after dialyzing by Sephadex G-75 column, showed two peaks at 150-200 kDa and 14-20 kDa by Sephacryl S-200 column. The nuclear 150-200 kDa receptor was also associated with the 14-20 kDa protein by DE52-cellulose column at 1.5-2.5 M KCl. The binding eluate at 1.5-2.5 M KCl on DE52 was estimated to be a 14-20 kDa protein and was not dissociated into two forms by Sephacryl S-200. The androgen specificity to the nuclear 14-20 kDa binding protein was emphasized by high ionic strength. This report presented the evidence that the cytosolic high mol wt receptor had the same character as the nuclear receptor in ionic condition and that the cytosolic high mol wt receptor was composed of a nuclear receptor and nontransformed binding protein.