PHARMACOKINETICS OF INHALED PYRENE IN RATS

Male Wistar rats were exposed to micronized aerosol concentrations of a C-14-labeled model polycyclic aromatic hydrocarbon (pyrene) at 200, 500, and 800 mg/m(3) for a period of 95 min. Both the C-14 label and f ree pyrene were monitored in the blood, urine, and feces. At the termi nation of the blood sampling, three of the six rats per dose group wer e killed and the distribution of [C-14]pyrene to eight major tissues w as analyzed. The analysis of blood concentration data using a one-comp artment pharmacokinetic model revealed that the uptake and elimination kinetic parameters were dose dependent, for both total radioactivity (pyrene plus metabolites) and for pyrene per se, over the range of exp osures used in this study. The ratio of the percent excreted via the u rinary and fecal routes, collected over a 5-d period postexposure was about 1.0 at each exposure level.