Protective effect of testosterone or 5 beta-dihydrotestosterone pretreatment on CFU-E numbers in busulfan-treated rabbits.

Busulfan is known to damage hematological stem cells. On the other hand, numerous steroid hormones have a stimulating effect on hematopoiesis. We wished to find out whether steroids have a protective effect on hematopoiesis in the case of busulfan treatment. This possibility was tested in vitro in rabbit bone marrow cultures, with and without in vivo pretreatment, with regard to erythropoiesis. The stimulating effect of testosterone or 5 beta-dihydrotestosterone on the CFU-E number in rabbit bone marrow cultures was blocked in the presence of busulfan. When rabbits were pretreated with either steroid before the administration of busulfan, however, the reduction of the CFU-E number seen after busulfan therapy alone was compensated. These results indicate that testosterone and the nonandrogenic 5 beta-dihydrotestosterone provide some protective effect on erythroid precursor cells when administered with reference to the cell-cycle-dependent action of busulfan.