Sasso-AF; Schlosser-PM; Kedderis-GL; Genter-MB; Snawder-J; Li-Z; Rieth-S; Lipscomb-JC
Toxicol Sci 2013 Feb; 131(2):360-374
Physiologically-based pharmacokinetic (PBPK) models are tools for interpreting toxicological data, and extrapolating observations across species and route of exposure. Chloroform (CHCl(3)) is a chemical for which there are PBPK models available in different species, and multiple sites of toxicity. Since chloroform induces toxic effects in the liver and kidneys via production of reactive metabolites, proper characterization of metabolism in these tissues is essential for risk assessment. While hepatic metabolism of chloroform is adequately described by these models, there is higher uncertainty for renal metabolism due to a lack of species-specific data and direct measurements of renal metabolism. Furthermore, models typically fail to account for regional differences in metabolic capacity within the kidney. Mischaracterization of renal metabolism may have a negligible effect on systemic chloroform levels, but it is anticipated to have a significant impact on the estimated site-specific production of reactive metabolites. In this paper, rate parameters for chloroform metabolism in the kidney are revised for rats, mice, and humans. New in vitro data were collected in mice and humans for this purpose and are presented here. The revised PBPK model is used to interpret data of chloroform-induced kidney toxicity in rats and mice exposed via inhalation and drinking water. Benchmark dose (BMD) modeling is used to characterize the dose-response relationship of kidney toxicity markers as a function of PBPK-derived internal kidney dose. Applying the PBPK model, it was also possible to characterize the dose-response for a recent dataset of rats exposed via multiple routes simultaneously. Consistent BMD modeling results were observed regardless of species or route of exposure.
Pharmacodynamics; Physiological-chemistry; Physiological-factors; Physiological-testing; Laboratory-animals; Laboratory-testing; Chemical-kinetics; Chloromethanes; Methanes; Toxic-effects; Toxicology; Analytical-models; Analytical-processes; Renal-toxicity; Kidneys; Metabolic-rate; Metabolism; In-vitro-study; Humans; Metabolites; Drinking-water; Dose-response;
Author Keywords: PBPK; chloroform; kidney; renal toxicity; model
A. F. Sasso, National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, 1200 Pennsylvania Avenue, NW, Washington, DC 20460, USA
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