Metabolism and Tissue Distribution of Orally Administered Trichloroethylene in Male and Female Rats: Identification of Glutathione- and Cytochrome P-450-Derived Metabolites in Liver, Kidney, Blood, and Urine

Abstract

Male and female Fischer 344 rats were administered trichloroethylene (TRI) (2, 5, or 15 mmol/kg body weight) in corn oil by oral gavage, and TRI and its metabolites were measured at times up to 48 h in liver, kidneys, blood, and urine. Studies tested the hypothesis that gender-dependent differences in distribution and metabolism of TRI could help explain differences in toxicity. Higher levels of TRI were generally observed in tissues of males at lower doses. Complex patterns of TRI concentration, sometimes with multiple peaks, were observed in liver, kidneys, and blood of both males and females, consistent with enterohepatic recirculation. Higher concentrations of cytochrome P-450 (P450)-derived metabolites were observed in livers of males than in females, whereas the opposite pattern was observed in kidneys. Trichloroacetate was the primary P450-derived metabolite in blood and urine, although it generally appeared at later times than chloral hydrate. Trichloroethanol was also a significant metabolite in urine. S-(1,2-Dichlorovinyl)glutathione (DCVG) was recovered in liver and kidneys of female rats only and in blood of both males and females, with generally higher amounts found in females. S-(1,2-Dichlorovinyl)-l-cysteine (DCVC), the penultimate nephrotoxic metabolite, was recovered in male and female liver, female kidneys, male blood, and in urine of both males and females. The relationship between gender-dependent differences in distribution and metabolism of TRI and susceptibility to TRI-induced toxicity is discussed.

We thank Jan Crowley, Washington University, St. Louis, MO, for NMR analysis of DCVC, DCVG, and NAcDCVC. This study was supported by a cooperative agreement with the U.S. Environmental Protection Agency (CR-824183) and National Institute of Environmental Health Sciences Grant R01-ES08828 to L. H. Lash. The views expressed in this article are those of the authors and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency.