ASSESSMENT OF THE ABILITY OF PROPOXUR, METHOMYL, AND ALDICARB, 3 CARBAMATE INSECTICIDES, TO INDUCE MICRONUCLEI IN-VITRO IN CULTURED CHINESE-HAMSTER OVARY CELLS AND IN-VIVO IN BALB C MICE/

Three carbamate insecticides (propoxur, methomyl, and aldicarb) were e valuated for their ability to induce micronuclei (MN) in vitro using c ultured Chinese hamster ovary (CHO) cells, and in vivo in mouse bone m arrow erythrocytes. In vitro, all three insecticides induced a signifi cant increase in micronucleated binucleate cells, which was generally both dose and sample time dependent. The in vivo studies involved trea ting male BALB/c mice by different routes, either once or on 3 consecu tive days, followed by multiple or single sampling. Treatment by intra peritoneal injection or oral gavage induced a significant increase in micronucleated reticulocytes (MNRETs) in peripheral blood. For all thr ee chemicals, the MN response depended on sample time and the number o f treatments, while For aldicarb, the response depended also on the ro ute of exposure. These positive results demonstrate that propoxur, met homyl, and aldicarb are capable of inducing structural and/or numerica l chromosomal aberrations in mammalian cells either in vitro or in viv o. Furthermore, based on the results obtained, an optimal in vivo MN p rotocol for carbamate insecticides is a single treatment Followed by b lood sampling at 24 and 48 hr after treatment. (C) 1997 Wiley-Liss, In c.