Effect of colchicine on the depletion and replenishment of cytoplasmic glucocorticoid receptor in rat liver after administration of glucocorticoid.

Pretreatment of rats with colchicine (3 mg/kg body weight) modified the time course of depletion of the cytoplasmic binding sites for 3H-dexamethasone after administration of prednisolone (0.5 or 1.5 mg/kg body weight). Colchicine also decreased the rate of the cytoplasmic receptor replenishment which was confirmed by application of this drug after completion of the cytoplasmic receptor translocation to nuclei (30 min after prednisolone injection). Addition of colchicine to the incubation mixture for in vitro binding of 3H-dexamethasone-labelled liver cytosol to isolated liver nuclei suspended in TKMS buffer (50 mM Tris-HCl, pH 7.5, 50 mM KCl, 5 mM MgCl2 and 250 mM sucrose) evoked no measurable changes in the rate of the nuclear binding.