Mirex lethal

Compounds that affect activities of hepatic microsomal enzymes can antagonize the effects of methyl parathion, presumably by decreasing metabolism of methyl parathion to methyl paraoxon or enhancing degradation to relatively nontoxic metabolites. For example, pretreatment with phenobarbital protected rats from methyl parathion s cholinergic effects (Murphy 1980) and reduced inhibition of acetylcholinesterase activity in the rat brain (Tvede et al. 1989). Phenobarbital pretreatment prevented lethality from methyl parathion in mice compared to saline-pretreated controls (Sultatos 1987). Pretreatment of rats with two other pesticides, chlordecone or mirex, also reduced inhibition of brain acetylcholinesterase activity in rats dosed with methyl parathion (2.5 mg/kg intraperitoneally), while pretreatment with the herbicide linuron decreased acetylcholine brain levels below those found with methyl parathion treatment alone (Tvede et al. 1989). 

Wolfe, J.L., R.J. Esher, K.M. Robinson, and J.D. Yarbrough. 1979. Lethal and reproductive effects of dietary mirex and DDT on old-field mice, Peromyscus polionotus. Bull. Environ. Contam. Toxicol. 21 397-402. Wood, P.B., C. Vivarette, L. Goodrich, M. Pokras, and C. Tibbott. 1996. Environmental contaminant levels in sharp-shinned hawks from the eastern United States. Jour. Raptor Res. 30 136-144. 

Cai Z, Mehendale HM. 1990. Lethal effects of carbon tetrachloride and its metabolism by Mongolian gerbils pretreated with chlordecone, phenobarbital, or mirex. Toxicol Appl Pharmacol 104(3) 511-520. 

Khera KS, Villeneuve DC, Terry G, et al. 1976. Mirex A teratogenicity, dominant lethal and tissue distribution study in rats. Food Cosmet Toxicol 14 25-29. 

Wolfe JL, Esher RJ, Robinson KM, et al. 1979. Lethal and reproductive effects of dietary mirex and DDT on old-field mice, Permyscus polionotus. Bull Environ Contam Toxicol 21 397-402. 

Mirex is more toxic with repeated dosing. Lethality was increased in adult male rats at dosages as low as 5 mg kg day for 30 days and in adult females at dosages as low as 6.2 mg kg day for 90 days. In... 

The remarkably amplified lethality (Table IX 2,10, 137-141) is unprecedented. The highly unusual aspect of the interaction is that mirex, a closely related structural analog does not potentiate haloalkane hepatotoxlclty with nearly the propensity... 

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