Failure of Tumor Promoter 12-0-Tetra- Decanoylphorbol-13-Acetate to Displace Estradiol from Its Specific Receptor

A permanent cell line derived from rat endometrium which contains a specific, low capacity, high affinity estrogen binding protein in cytosol and nuclear fractions (estrogen receptor) is available. Extracts of cells from this line did not appreciably bind the tumor promoter, 12-0-tetradecanoylphorbol-13-acetate. The result suggests that the action of the promoter does not involve translocation to the cell nucleus via binding to the specific estrogen receptor.