Comparison of the effects of dexamethasone 21-acetate and corticosterone on glucocorticoid cytosol receptor depletion and induction of TAT in rat liver.

Rapid fall in the amount of glucocorticoid cytosol receptor in target tissues is considered to be a consequence of the receptor translocation to nuclei. The effect of single injection of synthetic (dexamethasone 21-acetate) and natural (corticosterone) glucocorticoid on the depletion and replenishment of cytoplasmic glucocorticoid receptor in rat liver was compared. The effect of 20 micrograms dexamethasone 21-acetate on the extent and duration of the decrease of 3H-dexamethasone binding in cytosol was significantly higher than that of 100 micrograms corticosterone. A direct relationship between the amount of depleted receptor and the kinetics of TAT induction was observed. In conclusion, the depletion and replenishment of cytosol receptor closely correlated with the biological potency of the steroid administered.