Differential regulation of the ERα protein by planar and nonplanar estrogens. MC2 (A), JM6 (B), MCF7:WS8 (C), MCF7:5C (D) cells were treated with E2 (1 nM), DES (1 nM), equilin (1 nM), estrone (1 nM), equilenin (1 nM), 3OHTPE (1 µM), EtOX (1 µM), bisphenol (1 µM), 4OHT (1 µM), endox (1 µM), baze (1 µM), ral (1 µM), and cell lysates were analyzed by Western blotting by anti-ERα antibody. Blot was reprobed by anti-actin antibody.