Biophysical parameters of glucocorticoid-binding proteins from rat inflammatory tissues

The complexes of [3H]glucocorticoid and cytoplasmic proteins of the inflammatory tissue were characterized by the gel filtration and by the sucrose density gradient centrifugation. Protein-bound [3H]cortisol sedimented at about 4 S with a Stokes radius of about 4 nm and an apparent molecular weight (Mr) of about 70 kDa, irrespective with the presence of 0.4 M KCl. The complex of [3H]triamcinolone acetonide (TAA) and protein sedimented at about 7 S and showed about 170 kDa of Mr and about 6 nm of the Stokes radius in the absence of 0.4 M KCl. In the presence of 0.4 M KCl, the [3H]TAA-protein complex changed into a smaller form (4 S) with about 4 nm of the Stokes radius and about 60 kDa of Mr. This suggests that the so-called glucocorticoid receptor of the inflammatory tissue associates with a 110 kDa protein.