A, Analysis of uterine wet weights. Adult ovariectomized wild-type mice (n = 10-12 mice in each group) were given single injections of oil, E2 (4 μg/kg), kepone (K, at 7.5, 15 or 30 mg/kg) or multiple injections of K [3X at 7.5 mg/kg, K-7.5 (M)], and killed 24 h after the last injection. In addition, ovariectomized ERα(−/−) mice (n = 5-7 mice in each group) were subjected to kepone (30 mg/kg) and oil, and killed at 24 h. *Values are statistically different (p<0.001), based on ANOVA (F = 99.7, df = 29) followed by Dunnett t-test. B, BrdU incorporation into DNA. Similar to the above experiments in A, mice were injected with BrdU (50 mg/kg, ip) 2h before killing. Formaldehyde fixed paraffin-embedded tissue sections were stained for BrdU incorporation as described in the Materials and Methods. Representative data are shown from the analysis of at least 5 different mice for each group. tissue sections are shown. Reddish-brown nuclear deposits (as shown by dark black spots in the nuclei of epithelial cells) indicate sites of positive immunostaining. le, luminal epithelium; ge, glandular epithelium. C, Quantitation of BrdU- or Ki-67-positive cells. The data presented here after the analysis of at least 5 different mice from each group. *Values are statistically different (p<0.001) against the oil (control), based on ANOVA (BrdU: F = 1782, df = 29; Ki-67: F = 1755, df = 29) followed by Dunnett t-test. D, Analysis of uterine cell proliferation by BrdU or Ki-67 in ERα(−/−) mice. Adult ovariectomized ERα(−/−) mice were given injections (sc) of oil or kepone (30 mg/kg) and analyzed after 24 h. Representative data are shown from the analysis of at least 5 different mice for each group. le, luminal epithelium.