Materials and Methods: Thirty-four young adult female mice were divided equally into estradiol valerate (EV) treated and control groups. Mice in experimental group (n = 18) received a single dose injection of EV (IM, 4 mg/kg). Weight and fertility rate of all mice were recorded. Morphology of ovarian follicles was assessed too. Chi-square and independent t test were used for comparison between groups. P value less than 0.05 was considered as significant level.

Results: After 60 days, the weight of EV-treated mice was significantly lower than control (P < 0.04) and the experimental group did not show any significant changes in their body weight. Fertility rate in experimental group was significantly lower (P < 0.001) than the other group. Follicle count showed that the number of preovulatory follicles and corpora lutea were lower (P < 0.001) and atretic follicles were higher (P < 0.001) significantly in EV-treated group in comparison to control. However, there were no significant differences in the number of primary, preantral and antral follicles between two groups.

Conclusion: The polycystic ovary morphology can be induced in adult mice with a single dose of EV. This model may help to improve our knowledge on all aspects of PCOS.