Hormone receptors of the baboon cardiovascular system. Biochemical characterization of myocardial cytoplasmic androgen receptors.
Using the synthetic androgen R1881 (17 beta-hydroxy-17alpha-methyl-estra-4, 9, 11-trien-3-one) as probe, we identified cytoplasmic androgen receptors in baboon myocardium. The relative binding affinity of selected steroids for the androgen receptor was R1881, 100%; 5alpha-dihydrotestosterone, 32.6%; testosterone, 29.6%, progesterone, 7.2%; R5020, 1.0%; and estradiol-17beta, 5.8%. The androgen receptor migrated on low ionic strength linear sucrose density gradients as a macromolecule with a sedimentation coefficient of 8.5S. Saturation analysis performed at 2 degrees C (available sites) showed that the androgen receptor content of baboon myocardial cytoplasmic extracts was 5.9 +/- 1.4 fmol/mg protein and that the dissociation constant for R1881 was 1.16 +/- 0.30 nM. These cytoplasmic androgen receptors  are indicated to be physiologically functional by previous autoradiographic studies (McGill et al., 1980; McGill and Sheridan, 1981) that showed localization of radioisotope in nuclei of myocardial fibers following injection of baboons with 5 alpha-dihydrotestosterone.
D000818:Animals; D001665:Binding Sites; D002319:Cardiovascular System / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D003593:Cytoplasm / Q000032:analysis*; D003600:Cytosol; D013196:Dihydrotestosterone / Q000378:metabolism; D004963:Estrenes / Q000378:metabolism; D005260:Female; D007185:Incubators; D015741:Metribolone; D009206:Myocardium; D010215:Papio; D011944:Receptors, Androgen; D011956:Receptors, Cell Surface; D013696:Temperature; D013739:Testosterone / Q000378:metabolism; D013997:Time Factors
D004963:Estrenes; D011944:Receptors, Androgen; D011956:Receptors, Cell Surface; D013196:Dihydrotestosterone; D015741:Metribolone; D013739:Testosterone