Analysis of cytogenetic damage induced in CHO cells by the pyrethroid insecticide fenvalerate.

A synthetic pyrethroid insecticide, fenvalerate, was tested for its ability to induce chromosome aberrations (CA) and sister chromatid exchanges (SCE) in CHO cells. Fenvalerate was assayed both in the presence and in the absence of a rat liver activation system (S9-mix). Our results indicate that fenvalerate in the presence of S9-mix is able significantly to increase the frequency of CA, while in the SCE test this increase occurred both in the presence and in the absence of S9-mix. In addition, fenvalerate affected the cell cycle, causing a decrease in the mitotic index (MI) and in the proliferative rate index (PRI).