Characterization of a cytoplasmic androgen receptor in the ram testis.
An androgen receptor has been characterized in the cytosol fraction of testes from hypophysectomized adult rams after in vitro labelling with [3H]testosterone. It can be distinguished from the testicular androgen-binding protein (ABP) and from the plasma 5 alpha-dihydrotestosterone-binding protein by electrophoresis on 3.25% acrylamide gels (Rx = 0.5) and on agar gels (anodic migration). It sediments in the 4S region in sucrose gradient containing 0.4 M KCl. Its complex with testosterone dissociates very slowly (t 1/2 = 29 h at 0 degrees C), and is destroyed by heating at 50 degrees C for 30 min and by pronase. Its relative affinities for steroids are 5 alpha-DHT greater than T greater than 5 alpha-androstanediols greater than cyproterone acetate greater than estradiol greater than progesterone. The number of binding sites is limited (about 20 fmoles/mg protein) and the apparent equilibrium dissociation constant (KD) is 5 x 10(-9) M.
D000327:Adsorption; D000728:Androgens / Q000097:blood; D000818:Animals; D002499:Centrifugation, Density Gradient; D003600:Cytosol / Q000378:metabolism; D004587:Electrophoresis, Agar Gel; D004591:Electrophoresis, Polyacrylamide Gel; D007016:Hypophysectomy; D007700:Kinetics; D008297:Male; D011944:Receptors, Androgen / Q000302:isolation & purification*; D011987:Receptors, Steroid / Q000302:isolation & purification*; D012152:Rete Testis / Q000378:metabolism*; D012756:Sheep; D013379:Substrate Specificity; D013737:Testis / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism*
D000728:Androgens; D011944:Receptors, Androgen; D011987:Receptors, Steroid; D013739:Testosterone