Effect of tamoxifen on vaginal estradiol receptor concentration. Total estradiol receptor concentration was determined by radioligand binding assay in vaginal tissue extracts from control (CONT) and tamoxifen-infused (TMX) rats (see Figure 1). For relative comparison, estradiol binding in vaginal tissue extracts from control and ovariectomized (OVX) rats was determined in separate assays. Data are the mean ± SEM from 3 independent assays. *p < 0.05 versus control group.