Reproductive Organs by Repeated Dose Studies in Rats 12) Effects of Cyclophosphamide on Spermatogenesis

ABSTRACT 1[b deterrnine what is an appropriate administration period for evaluation of the testicular toxicity of cyclophospharnide, the compound was administered orally to male Cij:(CD)SD rats at doses of 5, 10, 20 and 40 mg/kg/day for 2 weeks and at doses of 2.5, 5 and 1 O mg/kgtday for 4 weeks. All animals in the 2-week treatment group given 40 mgfkglday died during the treatment period. After repeated dosing, weights of testes and epididymides did not change significantly in either 2-week or 4-week treatment groups, On conventional histopathological examination, changes in spermatogonia were too subtle to allow simple quantitative evaluation. Therefbre the quantitative analysis described by Matsui et at. (1995) was employed,