title: Androgen receptor in human placental villi.
abstract: In studies with a synthetic androgen, R 1881, an androgen-binding component was found in the cytosol of human placental villi. Kinetic analysis indicated that the Kd value of this component was 1.4 nM at 0-4 degrees C and that binding of R 1881 amounted to 277 +/- 73 fmol/mg protein. glycerol density gradient ultracentrifugation showed a peak of binding activity in the 8S region in a medium of low ionic strength, but in the 4.5S region in a medium containing 9.5 M KCl. The R 1881-binding component was inactivated by mild heat- or trypsin-treatment, but not by treatment with DNase or RNase. Most of the R 1881-binding activity was sedimented at 20 to 40% saturation of ammonium sulfate. These findings indicate that the R 1881-binding component in human placental cytosol is quite similar in its characteristics to androgen receptors, which are present in various androgen-responsive organs. Testosterone was a more potent competitor of R 1881-binding than DHT or cyproterone acetate. Scatchard plots indicated that the binding site of testosterone was identical with that of R 1881. These findings suggest that the androgen receptor in placental cytosol is specific for testosterone. The Kd value for testosterone was calculated to be 3.2 nM.
mesh_terms: D002462:Cell Membrane / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism; D004963:Estrenes / Q000378:metabolism; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D015741:Metribolone; D008871:Microvilli / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011397:Promegestone / Q000494:pharmacology; D011944:Receptors, Androgen / Q000378:metabolism*; D011987:Receptors, Steroid / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism; D045165:Testosterone Congeners / Q000378:metabolism
chemical_list: D004963:Estrenes; D011944:Receptors, Androgen; D011987:Receptors, Steroid; D045165:Testosterone Congeners; D015741:Metribolone; D013739:Testosterone; D004958:Estradiol; D011397:Promegestone