The genotoxic potential of paraquat was evaluated in mouse somatic (bo
ne marrow) and germ (spermatozoa) cells. Two exposure schedules were c
onducted: single and multiple treatment. Only for multiple treatment w
as an increased frequency of chromosomal aberrations observed. In germ
cells, paraquat induced an increase of sperm-shape abnormalities when
the animals were treated at three stages of cell development: spermat
ozoa, spermatid and preleptotene spermatogonial cells. These toxicogen
etic effects might be attributed to the ability of paraquat to generat
e oxygen free radicals.