Bisphenol A has been shown to affect the reproduction of male rats and mice. 
However, the mechanism of action of bisphenol A on the epididymal sperm is not 
elucidated. The present study was undertaken to evaluate the effect of bisphenol 
A on the antioxidant system of rat epididymal sperm. Bisphenol A was 
administered orally to male rats at the dose levels of 0.2, 2 and 20 microg/Kg 
body weight per day for 45 days. After 24 h of the last treatment, rats were 
weighed and killed using anesthetic ether. The body weight of treated rats did 
not show significant change as compared with the corresponding control groups. 
In bisphenol A-treated rats there was a significant decrease in the weight of 
the testis and epididymis; the weight of ventral prostate increased 
significantly whereas there was no significant change in the weight of seminal 
vesicles as compared with the corresponding group of control animals. Sperm 
collected from the epididymis were used for sperm count and biochemical 
estimations. Administration of bisphenol A caused a reduction in the epididymal 
sperm motility and sperm count in a dose-dependent manner. The activities of 
superoxide dismutase, catalase, glutathione reductase and glutathione peroxidase 
were decreased while the levels of H(2)O(2) and lipid peroxidation increased 
significantly in the treated rats as compared with the corresponding group of 
control animals. The results suggested that graded doses of bisphenol A elicit 
depletion of antioxidant defence system and induce oxidative stress in 
epididymal sperm of rats. In conclusion, the adverse effect of bisphenol A on 
male reproduction may be due to induction of oxidative stress in sperm.