We investigated spermatogenic damage induced by anti-cancer agents in previous studies. The results showed that the damage to spermatogenesis induced by anti-cancer agents could be due to not only direct damaging effects on DNA synthesis but also a direct effect on Sertoli cell function. Thus, stimulating Sertoli cell function could protect against the damaging effects of anti-cancer agents on spermatogenesis, or stimulate recovery from impair spermatogenesis. We experimented with rats injected with the anti-cancer agents cisdiamminedichloroplatinum (CDDP) and adriamycin, which impair spermatogenesis, in order to examine this hypothesis. Follicle-stimulating hormone (FSH), which should stimulate Sertoli cell function in vivo, was selected, and the effects of FSH in protecting against damage or stimulating recovery from damage were investigated. The injection of FSH resulted in no significant differences in the histopathological findings of spermatogenic damage induced by anti-cancer agents or testicular transferrin concentration as compared to those observed without FSH injection. But, in the protocol of the experiments on acceleration of recovery from spermatogenic damage induced by anti-cancer agents, the spermatid index without FSH was 1.02 +/- 0.24, that with FHS 75 IU/kg was 1.50 +/- 0.15, and that with FSH 150 IU/kg was 1.62 +/- 0.39, a significant difference (p < 0.05). Also, the PCNA labeling index and testicular transferrin concentration were significantly different with FSH from those without FSH.