The nuclear binding of dexamethasone-receptor complex from fast and slow skeletal muscle in rats.

1. The binding to isolated muscle nuclei of the complex of dexamethasone with cytosol receptors from rat soleus (Sol) and extensor digitorum longus (EDL) muscles was measured. 2. The ratio of bound to total amount of complex was higher in Sol. 3. The binding of complex per mg of cytosol protein was also higher in Sol. 4. These results suggest that activation and nuclear binding of the steroid-receptor complex are not the sites of the different sensitivity of the two muscle types to glucocorticoid.