AIM: To investigate the effects of genistein( GST) and 17 βestradiol (E2 ) on the reproductive system in
ovariectomized
rats. METHODS: Forty adult Sprague Dawley female rats were randomly divided into five groups: the Sham
ovariectomized (Sham), the ovariectomized (OVX), the 17β estradiol (E 2, 400 μg/㎏/d), the GST higher dosage (GST h, 50 mg/kg/d) and the GST lower dosage (GST L, 25 mg/kg/d). After treatment for 6 weeks, the level of serum estradiol was detected by radioimmunoassay in all the animals. All of the ovariectomized rats were sacrificed to measure the percentage of vaginal keratinized epithelial cells. Body weight and uterus index were also determined in all the animals. RESULTS: 17β estradiol treatment obviously increased the serum estradiol concentration, uterus index and the percentage of vaginal keratinized epithelial cells in OVX rats ( P <0.001 vs OVX). Genistein at a lower dosage significantly increased the uterus index and the percentage of vaginal keratinized epithelial cells in OVX rats ( P <0.001 vs OVX), but genistein at a higher dosage did not augment the uterus index and the percentage of vaginal keratinized epithelial cells in OVX rats ( P >0.05 vs OVX). The treatment with either a higher or a lower dosage of genistein did not alter the serum estradiol level following bilateral
ovariectomy. CONCLUSION: Genistein at a lower dosage plays a milder estrogen like role in the reproductive system of ovariectomized rats, but its effects are significantly less than that of estrogen. Genistein at a higher dosage plays an inhibitive role in the reproductive system of ovariectomized rats.