Effect of prenatal treatment with busulfan on the hypothalamo-pituitary axis, genital tract and testicular histology of prepubertal male rats.

Female Wistar rats were treated with busulfan or with solvent on Day 20 of pregnancy. Thirty male offspring of each group were killed at 38 days of age. In busulfan-treated rats, compared to controls, hypothalamic LH-RH content was decreased by 52%, whereas pituitary LH and FSH concentrations were increased by 60 and 43% respectively. Plasma LH and FSH were increased by 112 and 275% respectively. Prolactin concentrations were not changed, but plasma testosterone concentration was decreased by 48%. The total number of Leydig cells per testis was decreased by 52%, and LH binding sites per testis were decreased by 70%. The total number of Sertoli cells was decreased by 44%, while FSH binding sites per testis were decreased by 62%. Spermatogenesis was practically absent after prenatal exposure to busulfan. These data demonstrate that on Day 20 of pregnancy all the dividing cells in the fetal testes were depleted by an antimitotic treatment. The stimulation of the hypothalamo-pituitary axis could have been partly induced by the decrease in testosterone production, and by the aplasia of germ cells involving modifications of the remaining Sertoli and Leydig cells.