Activation of the rat liver glucocorticoid--receptor complex.

The rat liver glucorcorticoid receptor has been activated using three procedures: heat, gel filtration, and dilution. With time after heat activation the steroid--receptor complex loses its capacity to bind to DNA--cellulose, while receptor activated by Sephadex G-25 and by dilution maintains DNA--cellulose binding capacity. The rates of steroid dissociation from nonactivated and activated receptor and essentially identical. However, nonactivated receptor is capable of rebinding steroid, while activated receptor has a reduced capacity to rebind steroid. The results of the gel filtration and dilution studies suggest that a low-molecular-weight factor(s) exists in rat liver cytosol which is involved in the process of activation.