Pharmacokinetic analysis of trichloroethylene metabolism in male B6C3F1 mice: Formation and disposition of trichloroacetic acid, dichloroacetic acid, S-(1,2-dichlorovinyl)glutathione and S-(1,2-dichlorovinyl)- l-cysteine

• Published in: Toxicology and applied pharmacology 2009-07, Vol.238 (1), p.90-99
• Main Authors: Kim, Sungkyoon, Kim, David, Pollack, Gary M., Collins, Leonard B., Rusyn, Ivan
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; Administration, Oral; Animals; Biological and medical sciences; BIOLOGICAL AVAILABILITY; BIOLOGICAL MARKERS; CARCINOGENS; Carcinogens - pharmacokinetics; Chemical and industrial products toxicology. Toxic occupational diseases; CHLORINATED ALIPHATIC HYDROCARBONS; CYSTEINE; Cysteine - analogs & derivatives; Cysteine - pharmacokinetics; Dichloroacetic acid; Dichloroacetic Acid - pharmacokinetics; GLUTATHIONE; Glutathione - analogs & derivatives; Glutathione - metabolism; Glutathione - pharmacokinetics; Half-Life; HUMAN POPULATIONS; KIDNEYS; Male; MALES; Medical sciences; METABOLISM; METABOLITES; MICE; Models, Biological; OXIDATION; Oxidation-Reduction; OXIDES; Pharmacokinetics; RATS; RISK ASSESSMENT; S-(1,2-dichlorovinyl)- l-cysteine; S-(1,2-dichlorovinyl)glutathione; Solvents; Time Factors; TOXICITY; Toxicology; Trichloroacetic acid; Trichloroacetic Acid - pharmacokinetics; Trichloroethylene; Trichloroethylene - pharmacokinetics
• ISSN: 0041-008X; 1096-0333
• DOI: 10.1016/j.taap.2009.04.019

Trichloroethylene (TCE) is a well-known carcinogen in rodents and concerns exist regarding its potential carcinogenicity in humans. Oxidative metabolites of TCE, such as dichloroacetic acid (DCA) and trichloroacetic acid (TCA), are thought to be hepatotoxic and carcinogenic in mice. The reactive products of glutathione conjugation, such as S-(1,2-dichlorovinyl)- l-cysteine (DCVC), and S-(1,2-dichlorovinyl) glutathione (DCVG), are associated with renal toxicity in rats. Recently, we developed a new analytical method for simultaneous assessment of these TCE metabolites in small-volume biological samples. Since important gaps remain in our understanding of the pharmacokinetics of TCE and its metabolites, we studied a time-course of DCA, TCA, DCVG and DCVG formation and elimination after a single oral dose of 2100 mg/kg TCE in male B6C3F1 mice. Based on systemic concentration-time data, we constructed multi-compartment models to explore the kinetic properties of the formation and disposition of TCE metabolites, as well as the source of DCA formation. We conclude that TCE-oxide is the most likely source of DCA. According to the best-fit model, bioavailability of oral TCE was ∼ 74%, and the half-life and clearance of each metabolite in the mouse were as follows: DCA: 0.6 h, 0.081 ml/h; TCA: 12 h, 3.80 ml/h; DCVG: 1.4 h, 16.8 ml/h; DCVC: 1.2 h, 176 ml/h. In B6C3F1 mice, oxidative metabolites are formed in much greater quantities (∼ 3600 fold difference) than glutathione-conjugative metabolites. In addition, DCA is produced to a very limited extent relative to TCA, while most of DCVG is converted into DCVC. These pharmacokinetic studies provide insight into the kinetic properties of four key biomarkers of TCE toxicity in the mouse, representing novel information that can be used in risk assessment.