title: Testicular cytosol factors inhibit the binding of steroid-receptor complexes to chromatin.
abstract: Testicular and prostatic androgen-receptor complexes as well as uterine estradiol-receptor complexes, partially purified by ammonium sulfate precipitation (15-37%), were bound to germ cell chromatin. At equivalent concentrations, less testicular androgen-receptor complexes bound to chromatin than did the other two steroid-receptor complexes. Addition of a partially purified testicular androgen-receptor preparation with prostatic androgen-receptor or uterine estradiol-receptor preparation to the binding interaction mixture reduced the binding of either of the latter two steroid-receptor complexes to chromatin. These data suggest the presence of inhibitory factor(s) in the testicular receptor preparations. Testicular cytosols were fractionated by ammonium sulfate precipitation into fractions A (15-37% saturation), B (37-50%) and C (50-75%). All fractions inhibit binding of these steroid-receptor complexes to chromatin. Fractions A and B appear to be heat labile, while fraction C was more stable. Further fractionation of A and C fractions on DEAE cellulose yielded A1 and C1 (filtrates) as well as A2 and C2 (0.3 M NaCl eluents), respectively. Subfractions A1, A2, and C2 contained inhibitory factors for the binding of steroid-receptor complexes to chromatin while C1 showed no effect. These data demonstrated that testicular cytosol contains a variety of inhibitory factors which affect the binding of both androgen-receptor and estradiol-receptor complexes to chromatin.
mesh_terms: D000818:Animals; D002457:Cell Extracts / Q000494:pharmacology*; D002843:Chromatin / Q000378:metabolism*; D002848:Chromatography, DEAE-Cellulose; D004958:Estradiol / Q000378:metabolism; D005260:Female; D008297:Male; D011467:Prostate / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011944:Receptors, Androgen / Q000378:metabolism*; D011959:Receptors, Estradiol / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D013737:Testis / Q000166:cytology* / Q000187:drug effects; D014020:Tissue Extracts / Q000494:pharmacology*; D014599:Uterus / Q000378:metabolism
chemical_list: D002457:Cell Extracts; D002843:Chromatin; D011944:Receptors, Androgen; D011959:Receptors, Estradiol; D011960:Receptors, Estrogen; D014020:Tissue Extracts; D004958:Estradiol