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A possible role of multidrug resistance-associated protein 2 (Mrp2) in hepatic excretion of PCB126, an environmental contaminant: PBPK/PD modeling.

Lohitnavy-M; Lu-Y; Lohitnavy-O; Chubb-LS; Hirono-S; Yang-RS

Toxicol Sci 2008 Jul; 104(1):27-39

http://dx.doi.org/10.1093/toxsci/kfn026

20034631

3,3',4,4',5'-Pentachlorobiphenyl (PCB126) is a carcinogenic environmental pollutant and its toxicity is mediated through binding with aryl hydrocarbon receptor (AhR). Earlier, we found that PCB126 treated F344 rats had 110-400 times higher PCB126 concentration in the liver than in the fat. Protein binding was suspected to be a major factor for the high liver concentration of PCB126 despite its high lipophilicity. In this research, we conducted a combined pharmacokinetic/pharmacodynamic study in male F344 rats. In addition to blood and tissue pharmacokinetics, we use the development of hepatic preneoplastic foci (glutathione-S-transferase placental form [GSTP]) as a pharmacodynamic endpoint. Experimental data were utilized for building a physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model. PBPK/PD modeling was consistent with the experimental PK and PD data. Salient features of this model include: (1) bindings between PCB126 and hepatic proteins, particularly the multidrug resistance-associated protein (Mrp2), a protein transporter; (2) Mrp2-mediated excretion; and (3) a relationship between area under the curve of PCB126 in the livers and % volume of GSTP foci. Mrp2 involvement in PCB126 pharmacokinetics is supported by computational chemistry calculation using a three-dimensional quantitative structure-activity relationship model of Mrp2 developed by S. Hirono et al. (2005, Pharm. Res. 22, 260-269). This work, for the first time, provided a plausible role of a versatile hepatic transporter for drugs, Mrp2, in the disposition of an important environmental pollutant, PCB126.

Work-environment; Models; Mathematical-models; Hepatotoxicity; Hepatotoxins; Physiological-chemistry; Physiological-response; Physiopathology; Quantitative-analysis; Environmental-pollution; Chemical-hypersensitivity; Chemical-properties; Author Keywords: carcinogenesis; disposition; physiologically based pharmacokinetics; polychlorinated biphenyls; PCB 126; Mrp2

Raymond S. H. Yang, Quantitative and Computational Toxicology Group, Department of Environmental and Radiological Health Sciences, Colorado State University, 137A Physiology Building, Fort Collins, CO 80523-1680

TOSCF2

20080701

Journal Article

raymond.yang@colostate.edu

Grant

2008

Grant-Number-R01-OH-007556; Grant-Number-T42-OH-008433

1

1096-6080

Research Tools and Approaches: Risk Assessment Methods

Toxicological Sciences

CO; WA

Colorado State University - Fort Collins