Identification and partial characterization of glucocorticoid receptors in human liver

In normal human liver from adult males and females cytoplasmatic components which bind dexamethasone specifically and with high affinity, were demonstrated via dextran-coated charcoal assay, agar gel electrophoresis, isoelectric focusing and sucrose gradient centrifugation. The apparent dissociation constant of the dexamethasone-binder complex was found to be 1.7 +/- 0.3 x 10-(8) mol/l. The binding capacity was limited to 67.5 +/- 5.3 fmol/mg of cytosol protein. The ligand specificity for binding to these components indicated the requirement for glucocorticoids. It was shown by means of agar gel electrophoresis that the dexamethasone-binding entities migrate to the receptor region of the gel. The isoelectric point of the binding components in human liver cytosol was found to be pH 6.3. Sedimentation in sucrose gradients revealed the bulk of these components to be in the 7S region. It is concluded that the specific dexamethasone-binding entities in human liver have all the properties of glucocorticoid receptors.