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Gregus, Z. ; Watkins, J.B. ; Thompson, T.N. ; Harvey, M.J. ; Rozman, K.K. ; Klaassen, C.

Hepatic phase I and phase II biotransformations in quail and trout: Comparison to other species commonly used in toxicity testing.

Toxicol. Appl. Pharmacol. 67, 430-441 (1983)
DOI PMC
Open Access Green as soon as Postprint is submitted to ZB.
The ability of quail and trout to perform a number of representative phase I and phase II biotransformations was examined. To facilitate interspecies comparisons, metabolism of the same substrates was examined simultaneously under uniform conditions for rat, mouse, rabbit, guinea pig, cat, and dog. Both nonmammalian species can metabolize four representative substrates of phase I mixed-function oxidases and one substrate of epoxide hydrolase, though activity tended to be lower than that of the mammals. Important differences in the conjugative pathways were also noted. Among these differences were the quail's relative deficiency in glutathione conjugation and the trout's low ability to conjugate sulfate compounds. Trout liver UDP-glucuronosyltransferase activity was remarkably high toward testosterone and bilirubin, while quail liver formed glucuronides of naphthol, p-nitrophenol, and digitoxigenin-monodigitoxoside. Also noteworthy was the high N-acetyltransferase activity of both quail and trout toward isoniazid, β-naphthylamine, and 2-aminofluorene. Differences in substrate specificity for a given enzymatic pathway may be an indication that multiple forms of drug metabolizing systems also occur in these nonmammalian species. Observation of several hundred- or even thousand-fold differences between species in their enzyme activities for certain substrates under uniform conditions reemphasizes the need for caution in extrapolation of xenobiotic metabolism from one species to another.
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Publication type Article: Journal article
Document type Scientific Article
ISSN (print) / ISBN 0041-008X
e-ISSN 1096-0333
Journal Toxicology and Applied Pharmacology
Quellenangaben Volume: 67, Issue: 3, Pages: 430-441 Article Number: , Supplement: ,
Publisher Elsevier
Reviewing status Peer reviewed
Institute(s) Departments & Institutes