[Biochemical and histological changes after acute oral poisoning with the acetanilide herbicide acetochlor]

Changes in the liver of male rats were studied on the 1, 3, 5, 7, 10 and 14 days after a single oral application of 1/5 DL 50 of the chloracetanilic herbicide Acetochlor (DL50 = 1063 mg/kg-1). Two main periods in the action of acetochlor can be identified: between 1-2 days when the influence of the compound itself is predominant and between 5-7 days, when the toxic action of the slowly eliminated metabolites is most pronounced. These two periods provoke a biphasic activation/inhibition response of the liver. Remarkable is the compensatory effect of the cytochrome P-450 system responsible for the metabolism of acetochlor. The phase-specific changes were are followed by pathomorphological observations of liver tissue as well as by the time-course of the biochemical parameters studied in different liver fractions.