Abstract: BACKGROUND ＆ AIM: To investigate the effects of prenatal exposure to exoestrogens diethylstilbestrol (DES) on the development of gubernaculum testis in fetal mice. MATERIAL AND METHODS: Sixty pregnant Kunming mice were divided into 6 groups randomly and administered subcutaneously from gestational day(GD) 9 though GD17 with DES at a dose of 25, 50, 100, 200 μg•kg－1•d－1 (all dissolved in 0.2 ml dimethyl sulfoxide(DMSO)) and with DMSO only(as control), normal saline alone (as normal control), respectively. Pregnant mice were sacrificed on GD19 and fetuses were quickly removed, the lower part of the male fetuses were fixed according to the need of study with light microscope, scanning and transmission electron microscope. RESULTS: In experimental groups, gubernaculum testis seemed underdeveloped, with smaller volume and abnormal shape, and the bulbs lose clear demarcation between the inner mesenchymal core and muscular outerlayer, gubernaculum cells had some smaller disordered myofibrils, and few fibrils could be seen in myofibrils, there were only some sparse organelles in cytoplasm. All these results closely related to the dosage of DES. CONCLUSION: DES could induce underdevelopment of gubernaculum testis of fetal male mice with obvious dose-effect correlation.

Key words: diethylstilbestrol, exoestrogens, gubernaculum, morphology