4CMB: investigation of activity in a mouse micronucleus test.

To study possible clastogenic effects of 4-chloromethylbiphenyl (4CMB), a mouse micronucleus test was performed (as part of the UKEMS genetic toxicology trial). Mice were given 4CMB by intraperitoneal injection, once daily for 5 consecutive days. Although the range of dosages employed included highly toxic or lethal doses, the frequency of micronucleated polychromatic erythrocytes in the bone marrow was not significantly greater in 4CMB-treated groups, than in control-group animals treated with the Tween 80 vehicle alone. Thus, in this test, 4CMB did not induce chromosomal damage resulting in micronucleus formation, in bone-marrow erythrocytes.