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A comparison of fish pesticide metabolic pathways with those of the rat and goat
Citation:
Kolanczyk, Rick, J. Serrano, M. Tapper, AND P. Schmieder. A comparison of fish pesticide metabolic pathways with those of the rat and goat. REGULATORY TOXICOLOGY AND PHARMACOLOGY. Elsevier Science Ltd, New York, NY, 94:124-143, (2018).
Impact/Purpose:
Limited availability of fish metabolic pathways for pesticides results in risk assessments with inherent uncertainties based upon the parent chemical only or the assumption that the rat metabolism map data will serve as an adequate surrogate. A database of rat metabolic maps are systematically compared to the available fish metabolism data found in the open literature for a limited set of well-studied pesticide chemical classes. This interim product develops a knowledgebase of xenobiotic metabolism in fish, targets data gaps for future fish metabolism laboratory studies, and provides an assessment of similarities and differences in metabolic products across species in an effort to reduce ecological risk assessment uncertainties.
Description:
Ecological risk assessments are often limited in their ability to consider metabolic transformations for fish species due to a lack of data. When these types of evaluations are attempted they are often based on parent chemical only, or by assuming similarity to available mammalian metabolic pathways. The metabolism maps for five pesticides (kresoxim-methyl, mandestrobin, tolclofos-methyl, halauxifen-methyl, and fluazinam) were compared across three species to better characterize and extrapolate biotransformation reactions across species. A rapid and transparent process, utilizing a database of systematically collected information for rat, goat, and fish (bluegill or rainbow trout), and using data evaluation tools in the previously described metabolism pathway software system MetaPath, is presented. The approach demonstrates how comparisons of metabolic maps across species is more accurately accomplished by considering the sample matrix in which metabolites were quantified for each species, differences in analytical methods used to identify metabolites in each study, and the relative amounts of metabolites quantified. By incorporating these considerations, more extensive rat and goat metabolism maps were found to be useful predictors of the more limited metabolism of the five pesticides in fish.
