In vivo metabolism of butadiene by mice and rats: a comparison of physiological model predictions and experimental data.

1,3-Butadiene (BD), a rodent carcinogen, is metabolized to mutagenic and potentially DNA-reactive epoxides, including butadiene monoepoxide (BMO) and butadiene diepoxide. A physiological model containing five tissue groups (liver, lung, fat, slowly perused tissues and rapidly perused tissues) and blood was developed to describe uptake and metabolism of inhaled BD and BMO. Minimal rates for hepatic and pulmonary metabolism of BD and hepatic metabolism of BMO incorporated into the model were extrapolated from in vitra data (Csanady et al., Carcinogenesis, 13, 1143-1153, 1992). Apparent enzyme affinities used in the model were identical to the values measured in vitro