Genotoxic and mono-oxygenase system effects of the fungicide maneb

The in vivo effects of a commercial preparation of maneb on mono-oxygenase activities of hepatic microsomes of basal and induced rats were examined. I n vitro experiments with the D7 strain of yeast Saccharomyces cerevisiae we re also performed. In both basal and induced rats maneb caused a decrease i n cytochrome P-450 content and aniline hydroxylase. Immunoblotting analysis using anti-P-450 IIE1 antibodies confirmed the data obtained for aniline h ydroxylase activity. Maneb was toxic in cells of S. cerevisiae. On the basi s of in vivo and in vitro experiments it can be concluded that maneb posses ses a toxic activity attributable to its main metabolite ethylene thiourea. Immunoblotting analysis indicates that maneb biotransformation influences the IIE1 P-450 isoform.