title: Androgen receptor protein in the androgen-dependent Dunning R-3327 prostate carcinoma.
abstract: The rat prostate carcinoma (Dunning R-3327) contains a relatively high concentration of androgen receptor (80 to 150 fmol/mg cytosol protein). We characterized this receptor for comparison with androgen receptors in normal organs of the rat. Binding of testosterone and dihydrotestosterone was of high affinity (Ka = 2 X 10(9) M). Rates of dissociation were slow (t 1/2 testosterone = 60 hr; t 1/2 dihydrotestosterone = approximately 160 hr). At low ionic strength, the receptor was in an 8S form which dissociated to 4.5 to 5.0S in the presence of 0.4 M KCl. Fractionation of [3H]dihydrotestosterone cytosol by chromatography on phosphocellulose yielded a single peak of radioactivity eluting at 0.2 M Cl-. Determination of size at high ionic strength by gel filtration chromatography and sucrose gradient centrifugation indicated a Stokes radius of 53 A and sedimentation coefficient of 5S (M.W. 115,000). Cytosols occasionally yielded a second peak of radioactivity eluting from phosphocellulose at 0.29 M Cl-. This fraction contained a smaller receptor [36 A, 3.6S (M.W. 55,000)]. Both receptor forms were observed in cytosols from the normal dorsal prostate. The larger high-salt form of the receptor is identical to native androgen receptor in normal tissues. Smaller receptor forms in the tumor and in normal androgen-responsive tissues have been shown previously to result from proteolytic cleavage of the native receptor during extraction.
mesh_terms: D000818:Animals; D002369:Castration; D003600:Cytosol / Q000378:metabolism; D013196:Dihydrotestosterone / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008970:Molecular Weight; D009374:Neoplasms, Experimental / Q000378:metabolism; D009376:Neoplasms, Hormone-Dependent / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000378:metabolism*; D051381:Rats; D011944:Receptors, Androgen / Q000378:metabolism*; D011987:Receptors, Steroid / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism
chemical_list: D011944:Receptors, Androgen; D011987:Receptors, Steroid; D013196:Dihydrotestosterone; D013739:Testosterone