cismethrin and bioresmethrin

Pyrethroids are potent synthetic insecticides which have been increasingly employed in recent years. Such compounds have been shown to bind covalently to hepatic proteins. Covalent binding is often associated with toxic effects. Possible cytotoxic, cytogenotoxic and allergenic effects could be due to covalent binding of these compounds and/or their metabolites to endogenous macromolecules. In the present paper we examine possible cytotoxic effects of certain pyrethroids on human lymphocytes and L 1210 lymphoblastoid mouse cells, cytogenotoxic effects with micronuclei test and allergenic effects with Magnusson and mast cell degranulation tests. Under our experimental conditions, the tested compounds showed neither acute cytotoxic nor cytogenotoxic effects, though, Cismethrin presented slight antimitotic effects statistically different to those with the control. Slight allergenic character of Cismethrin, Bioresmethrin and Deltamethrin was revealed by Magnusson and mast cell degranulation tests.

Topics: Animals; Cell Survival; Humans; Insecticides; Leukemia L1210; Lymphocytes; Mast Cells; Mice; Nitriles; Permethrin; Pyrethrins; Rats; Rats, Inbred Strains; Tumor Cells, Cultured

When [14C]Alcohol-labeled cismethrin, bioresmethrin, and 5-benzyl-3-furylmethyl alcohol (BFA) were incubated with rat liver S 9 homogenates or microsomes, a proportion of the radioactive compounds was covalently bound to proteins. The covalent binding was greater with phenobarbital-pretreated rats, and dependent on a NADPH-generating system. When a S 9 homogenate was used, the bound compounds were twofold higher for cismethrin than for bioresmethrin and BFA. Inversely, when microsomes were used more covalent binding occurred with bioresmethrin and BFA than with cismethrin. The inhibition of esterases by tetraethyl pyrophosphate (TEPP) in a S 9 homogenate did not alter the amount of covalent binding to the three compounds whereas malathion inhibited this binding. Treatment of a S 9 homogenate with piperonyl butoxide, however, greatly reduced covalent binding. Covalent binding was inhibited when the microsomes were incubated with carbon monoxide or modified by thermal denaturation. It is suggested that oxidative metabolism was responsible for the covalent binding.

Topics: Animals; Carbon Radioisotopes; Carboxylic Ester Hydrolases; Cytochrome P-450 Enzyme System; Drug Interactions; Electrophoresis; Female; Liver; Malathion; Microsomes, Liver; Mixed Function Oxygenases; NADP; Organophosphorus Compounds; Piperonyl Butoxide; Pyrethrins; Rats; Rats, Inbred Strains

Topics: Animals; Female; Hydrolysis; Liver; Microsomes, Liver; Peptide Hydrolases; Protein Binding; Pyrethrins; Rats; Rats, Inbred Strains; Ribonucleases; Subcellular Fractions