Metabolism and Defluorination of Fluoroacetate in the Brush-Tailed Possum (Trichosurus Vulpecula)

Abstract

The brush-tailed possum (T. vulpecula) from Western Australia was found to be nearly 150 times more resistant to fiuoroacetate intoxication in vivo than the same species from South Australia. Acetone powder preparations from the liver of animals from both populations showed similar abilities to convert fiuoroacetate into fiuorocitrate. Aconitate hydratase activity in liver preparations from both Western Australian and South Australian animals was similarly and competitively inhibited by fiuorocitrate. Both animals were capable of defiuorinating fiuoroacetate at similar rates by a glutathione-dependent enzymic mechanism resulting in the formation of free fiuoride ion and S-carboxymethylcysteine. Glutathione was also capable of partial protection against the toxic effects of fiuoroacetate in vitro by a further unelucidated mechanism.