Fig. 5.
Effects of ER antagonists on E2-induced whole-cell and non-nuclear ER increase. C2C12 cells were treated with E2 (10−8 M) in the absence or presence of either tamoxifen or ICI 182,780 (10−7 M; a total ER) or (10−5 M; b non-nuclear fractions) for 15 h. Tamoxifen or ICI 182,780 was added to the culture medium 30 min prior to the administration of E2. Total and nonnuclear fractions of ER were prepared as described in “Materials and methods” and subjected to Western blotting. Histograms represent the extent of inhibition of E2-induced ER increase in total a and nonnuclear b fractions, which are expressed as the percentage of control (no stimulation), averaged from five separate experiments (mean ± SE). *P < 0.01, compared with control values, determined using Student’s t test