Stabilization of estradiol-receptor complexes by elimination of cytosolic factors.

Treating mature rat uterine cytosol with dextran coated charcoal (DCC) for 2 hrs at 0-4C in the absence of ligand causes the subsequently formed receptor-estradiol complex to be stable at 37C. Receptor binding is increased by the DCC treatment for uteri excised at metestrus or diestrus but remains nearly unchanged for uteri obtained at proestrus or estrus. Results suggest that the DCC removes or inactivates factor(s) present in the cytosol which render the receptor complex thermolabile.