Examination of factors that may influence disposition of benzo[a]pyrene in vivo: vehicles and asbestos.

Effects of vehicles and of asbestos on disposition of benzo[a]pyrene (B[a]P) were examined in vivo. [3H]B[a]P dissolved in triethylene glycol, ethyl laurate, or tricaprylin was intratracheally administered to male Sprague-Dawley rats. Excretion was most rapid when triethylene glycol was the vehicle, with 70.5% of the recovered dose appearing in bile in 6 h. Lower amounts were excreted into bile when ethyl laurate (58.4%) or tricaprylin (56.2%) were the vehicles, with comparably higher amounts remaining in lungs. When chrysotile asbestos was intratracheally instilled 24 h prior to instillation of [3H]B[a]P dissolved in triethylene glycol, the rate of excretion of radioactivity was slower than without asbestos pretreatment, with only 61.8% of the dose appearing in bile in 6 h.