Identification of glucocorticoid receptors in normal and neoplastic adult human lung.

A dexamethasone-binding protein was detected in cytosol of five normal and three neoplastic lung tissue samples. The apparent dissociation constant of the dexamethasone protein complex ranged from 5.8 to 21 nM (11.4 +/- 5.7 nM for normal tissue cytosol, 12.1 +/- 7.7 nM for the neoplastic tissue cytosol). The binding protein sedimented at 8 S in sucrose density gradient at low ionic strength and showed a high specificity for glucocorticoids. It was concluded that the dexamethasone-binding protein had the characteristics of a glucocorticoid receptor. The glucocorticoid receptor content was determined to be 12-77 fmol/mg protein (37.1 +/- 18.9 fmol/mg protein for the normal tissue cytosol, 51.9 +/- 23.9 fmol/mg protein for the neoplastic tissue cytosol).