Absence of genetic and cytogenetic effects in mice treated by the organophosphorus insecticide parathion, its methyl analogue, and paraoxon.

Male mice (Q strain) received a single i.p. injection of 3 organophosphorus compounds: ethylparathion (10 mg/kg), its methyl analogue (methylparathion, 10 mg/kg), or its phosphate derivative (ethylparaoxon, 0.3 mg/kg). The number of chromosome aberrations observed in bone marrow cells and spermatogonia, and the frequency of pre- and postimplantation foetal lethality obtained in a dominant lethal mutation assay, did not conclusively prove that the tested compounds produced a mutagenic effect.