LACK OF GENOTOXICITY OF PIPERONYL BUTOXIDE

The genotoxicity of piperonyl butoxide has been investigated in bacter ial mutation assays using tester strains TA98, TA100, TA1535, TA1537 a nd TA1538. The assays were conducted both with and without metabolic a ctivation. Piperonyl butoxide was tested for mutation with and without metabolic activation in the CHO/HGPRT assay. Chromosomal aberrations were investigated also using Chinese hamster ovary (CHO) cells and eff ects on DNA were evaluated by in vitro unscheduled DNA synthesis (UDS) test using rat liver primary cell cultures. Piperonyl butoxide was no t shown to be genotoxic in any assay system. The data presented suppor ts the view that the liver tumors observed in rodents at dose levels a bove the maximally tolerated dose (MTD) result from a secondary non-ge notoxic mechanism.