Fig. 1. A rat model of benign prostate hyperplasia (BPH) was induced by daily injections of 5 mg/kg testosterone for 16 weeks after castration. Then, 0.075 mg/kg costunolide (CO), 0.075 mg/kg dehydrocostus lactone (DCL), or 0.8 mg/kg finasteride was administered orally to the rats for 8 weeks after induction. Values are expressed as mean±standard error of the mean (n=6). ^ap<0.05, ^bp<0.01, ^cp<0.001 compared to the control group. Statistical analyses were performed by ANOVA and Dunnett's multiple comparison test.