Abstract: Objective:To investigate the estrogenic effects of BPA and DES co-administered or administered single in the immature female SD rats,and to provide the scientific evidences for further study on the toxicological mechanism of environmental estrogens(EEs). Methods:The immature female SD rats (21 d) were administered with BPA (200,400, and 800 mg·kg^-1),DES (15 and 150 μg·kg^-1) and the mixture of BPA and DES (100 mg·kg^-1 BPA + 7.5 μg·kg^-1 DES,200 mg·kg^-1 BPA + 7.5 μg·kg^-1 DES,400 mg·kg-1 BPA+7.5 μg·kg^-1DES,400 mg·kg^-1 BPA + 75 μg·kg^-1 DES); at the same time,control group was set up. The uterine weights,the ratios of uterine weights to body weights,the heights of luminal epithelium,the thickness of myometrium,the amounts of uterine glands,and the amounts of mature follicle of the rats in various groups were observed. Results:The uterine weight,the ratio of uterine weight to body weight,the height of luminal epithelium,the thickness of myometrium,and the amount of uterine glands of the rats in 800 mg·kg^-1 BPA group were increased significantly compared with control group (P<0.05).The uterine weights,the ratios of uterine weights to body weights,the heights of luminal epithelium,the thickness of myometrium,the amount of uterine glands and the amounts of mature follicle in 15 and 150 μg·kg^-1 DES groups were significantly increased compared with control group (P<0.05).The uterine weights,the ratios of uterine weights to body weights,the heights of luminal epithelium,the thickness of myometrium,the amounts of uterine glands and the amount of mature follicle in combination groups with different doses were increased significantly(P<0.05),but had no changes compared with different doses of DES groups (P>0.05). Conclusion: BPA and DES use alone have the estrogenic activities,and the estrogenic effects of co-administered BPA and DES are additive.

Key words: estrogenic effects, bisphenol A, diethylstilbestrol, uterus growth assay