ATP-dependent activation of glucocorticoid-receptor complexes from the rat's heart

The effect of ATP on the cytosolic rat heart glucocorticoid receptor was studied by employing different methods for evaluation of the changes in molecular properties of the receptor, induced by activation. Incubation of triamcinolone acetonide labelled cytosol at 25 degrees C or with 10 mM ATP at 4 degrees C leads to the increase in the partition coefficient of the receptor in the aqueous dextran-polyethylene glycol two-phase system and also nuclear uptake of the complexes. The effect of ATP on the partition coefficient was more pronounced, compared with that of thermal treatment or dilution of the cytosol and totally inhibited by 10 mM sodium molybdate. The activating effect of ATP on the glucocorticoid-receptor complexes and sensitivity of this activation to sodium molybdate was also confirmed by DEAE-cellulose chromatography of cytosolic receptor preparations. The results suggest that ATP may be involved in the glucocorticoid receptor activation and through this regulates the translocation of complexes into the nucleus under in vivo conditions.