Zineb: effect on rat monooxygenase system and genotoxicity in yeast.

In vivo” effects of a commercial preparation of zineb on monooxygenase activities were examined on hepatic microsomes of induced and not induced (basal) rats. Moreover additional “in vitro” experiments with the D7 strain of yeast Saccharomyces cerevisiae and Salmonella typhimurium were performed. Our results show that zineb caused a decrease in cytochrome P-450 (cyt P-450) content and in some enzymatic activities such as aminopyrine-N-demethylase (APD), p-nitroanisole-O-demethylase (p-NAD) and aniline hydroxylase (AnH). Immunoblotting analysis, using anti P-450 2E1 antibodies, confirmed data obtained in AnH activity. Experiments on yeast Saccharomyces cerevisiae showed that zineb induced marked increase of gene conversion and point reverse mutation in logarithmic growth phase cells. Finally, in experiments with Salmonella typhimurium, zineb had not mutagenic effects. It can be concluded from “in vivo” and “in vitro” experiments that zineb has toxic action both in animals, expecially in basal rats, and in yeast cells, when it is metabolized; its biotransformation particularly influences 2E1 P-450 isoform.