The dexamethasone receptor in the Novikoff Hepatoma. Characterization and changes in concentration and nuclear uptake during glucocorticoid therapy.

Novikoff hepatoma ascites cells, grown intraperitoneally in rats, are shown to possess a high-affinity, low-capacity dexamethasone-binding protein. The receptor protein has an intracellular localization and concentration, association constant (Ka), glucocorticoid specificity and nuclear uptake in the presence of dexamethasone comparable with those of the G-protein of rat liver. During therapy of the tumour-bearing animal with cortisol, marked cyclic variations were observed in the concentration and nuclear uptake of the putative G-protein in the tumor cells; more transient variations were also observed in the Ka value of the receptor protein.