Comparative investigation of cyclophosphamide action on bone marrow cells of the Armenian hamster and 4 other species of rodents.

We studied the clastogenic action of cyclophosphamide (CP) on bone marrow cells of the Armenian hamster (AH), Cricetulus migratorius. CP induced a dose-dependent linear increase in aberrant cells. The maximal cytogenetic action was observed 12 h after CP treatment. Male and female AHs were similarly sensitive to the clastogenic action of CP. We compared CP clastogenicity at a dose of 25 mg/kg on bone marrow cells of AHs, mice, rats, guinea pigs and Chinese hamsters 24 h after treatment. We observed that this dose of CP induced only 2.8% aberrant cells in bone marrow of AHs, but 42.8%, 32.2%, 25% and 14.6% aberrant cells in bone marrow of guinea pigs, rats, mice and Chinese hamsters respectively. AHs are much more resistant to the metaphase-arresting action of colchicine than other species of rodents (e.g., the colchicine dose for AHs is 100-fold more than for rats). Thus AHs are the most resistant of all rodent species studied to the clastogenic action of CP.