Correlation of androgen-responsiveness of Shionogi mouse mammary carcinoma cell lines with binding of dihydrotestosterone to nuclear envelopes.
Purified nuclear envelopes have been isolated from an androgen-responsive and two androgen-unresponsive cell lines of the Shionogi mouse mammary carcinoma. The binding of dihydrotestosterone to nuclear envelope fractions isolated from the three variant cell lines is correlated with the androgen-responsiveness of the cell line. Nuclear envelopes prepared from the two androgen-unresponsive cell lines did not bind dihydrotestosterone specifically following incubation with radioactive dihydrotestosterone from 2.5 to 45.0 nM at 20 degrees C for 18 h. Under the same binding conditions, nuclear envelopes prepared from the androgen-responsive cell line demonstrated saturable, specific binding of dihydrotestosterone. Scatchard analysis revealed a class of binding sites with an apparent Kd of 14.2 nM and a maximum binding capacity of 28.7 fmol/mg protein. Proteinase and heat treatments resulted in the complete loss of androgen-binding activity, whereas DNAase treatment resulted in the loss of 38% of the binding activity. The binding sites were specific for dihydrotestosterone. Testosterone was only a weak competitor and estradiol did not compete. Extraction with concentrations of KCl up to 1.0 M did not result in loss of androgen binding.
D000818:Animals; D001667:Binding, Competitive; D002460:Cell Line; D013196:Dihydrotestosterone / Q000378:metabolism*; D004351:Drug Resistance; D004958:Estradiol / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008325:Mammary Neoplasms, Experimental / Q000378:metabolism / Q000648:ultrastructure*; D051379:Mice; D008854:Microscopy, Electron; D009685:Nuclear Envelope / Q000378:metabolism; D013739:Testosterone / Q000378:metabolism
D013196:Dihydrotestosterone; D013739:Testosterone; D004958:Estradiol