Pyrethroid metabolism: comparative fate in rats of tralomethrin, tralocythrin, deltamethrin, and (1R,.alpha.S)-cis-cypermethrin

• Published in: Journal of agricultural and food chemistry Vol. 30; no. 4; pp. 631 - 636
• Main Authors: Cole, Loretta M., Ruzo, Luis O., Wood, Edgardo J., Casida, John E.
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01.07.1982
• Subjects: Animals; Carbon Dioxide; Feces - analysis; Lethal Dose 50; Male; Mice; Models, Biological; Nitriles; Pyrethrins - metabolism; Pyrethrins - toxicity; Rats; Rats, Inbred Strains; Tissue Distribution
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf00112a003

The insecticides tralomethrin and tralocythrin, (S)- alpha -cyano-3-phenoxybenzyl cis-(1R,3R,1'R or S)-3-(1,2-dibromo-2,2-dimethylcyclopropane carboxylates, were compared with deltamethrin and (1R, alpha S)-cis-cypermethrin relative to their distribution, excretion, metabolic fate, and tissue residues following oral administration to male rats. Tralomethrin and tralocythrin are not normally detected in treated animals or their excreta since they undergo rapid and essentially complete debromination to form deltamethrin and (1R, alpha S)-cis-cypermethrin, respectively. Deltamethrin and cypermethrin are then hydroxylated at athe 2',4', and 5 positions of the alcohol moiety and the methyl group trans to the carboxylate linkage. Extensive ester cleavage reactions for deltamethrin and cypermethrin and further metabolism of the cleavage products yield the expected series of alcohols and carboxylic acids and their glucuronide, glycine, and sulfate conjugates. The cyano fragment is retained several days in the stomach and skin. Toxicity studies with mice provide evidence that intracerebrally administered tralomethrin and tralocythrin may be activated by debromination in the brain.