THE MICRONUCLEUS ASSAY IN MOUSE PERIPHERAL-BLOOD RETICULOCYTES DEMONSTRATES THE TRANSMISSION OF CHROMOSOMAL INSTABILITY INDUCED BY MITOMYCIN-C AND BENZO[A]PYRENE

The frequency of micronuclei (MN) in mouse peripheral blood reticulocy tes supravitally stained with acridine orange was assessed at differen t time intervals after treatment in vivo with two dose levels of mitom ycin C (MMC) and benzo[a]pyrene. Increased frequencies were observed f or many days after treatment, indicating that MN may be produced as a consequence of chromosomal instability transmitted by proliferating er ythroblasts. These results confirm previous evidence of the persistent cytogenetic effects of MMC and suggest that clastogenic agents acting by different primary lesions may have a similar ability to induce thi s effect.