ABSTRACT
In order to evaluate the effects of phenytoin on the reproductive system of rats in detail, 60 male rats were divided equally into 6 groups: 1-5 received 10 mg/kg/day phenytoin IP for 1,2,3,4 and 5 weeks, respectively. However, group 5 did not receive any phenytoin for the last 5th week. The control group [group 6] did not receive any treatment. The results revealed that phenytoin does not have any effect on body weight, weight of testes, seminal vesicle and prostate, serum testosterone and sperm count taken from left and right vas deferenses. However, the percentage of total motile sperm and sperm with full and sluggish motility decreased and the percentage of low motile sperm increased in all experimental groups. Nevertheless, phenytoin caused atrophy and hypoplasia in seminiferous tubules and not Leydig cells. These pathological changes were dose-dependent and more pronounced in the left testis. But phenytoin caused more changes in sperm count and motility of the right testis. This phenomenon was discussed in relation to the existence of asymmetrical control by the hypothalamus, and compensation of the left testis. In summary, it could be concluded that phenytoin affected the seminiferous tubules directly and decreased the total number of motile sperm. It was also discussed that these effects are not reversible after termination of injection