Zoological Studies

Genotoxicity of Methoxyphosphinyl Insecticide in Mammalian Cells

T.C. Wang, Chih-Min Lin and Li-Wen Lo (2003) The genotoxicity of 5 organophosphorus insecticides containing the methoxyphosphinyl subunit was assayed by examining the induction of sister-chromatid exchanges (SCEs), chromosome aberrations, and the hypoxanthine-guanine phosphoribosyl transferase (hgprt) gene mutations in CHO cells. Insecticides included acephate, dichlorvos, monocrotophos, methamidophos, and trichlorfon. They consistently induced significant SCEs, with the order of induction potential of acephate > trichlorfon > monocrotophos > methamidophos > dichlorvos. However, only 2 of them, dichlorvos and methamidophos, induced positive chromosome aberrations. Monocrotophos and acephate were questionable positive, while trichlorfon was negative for chromosome aberration induction. The order of chromosome aberration induction potential was dichlorvos > methamidophos > monocrotophos > acephate > trichlorfon. None of these 5 insecticides induced significant hgprt gene mutations compared to the concurrent negative control. The discrepancy between the results of the 2 cytogenetic endpoints, and the contradictory outcome between hgprt mutation and SCE are discussed, from which a possible mechanism of insecticide genotoxicity postulated.