Effects of asphalt fume condensate (AFC) exposure on the pulmonary cytochrome P450 (CYP450) system.
Ma-JYC; Yang-HM; Barger-M; Kreich-AJ; Castranova-V
FASEB J 2000 Mar; 14(4):A173
Exposure to asphalt fumes is a concern due to the presence of polycyclic aromatic hydrocarbons (PAH) in asphalt. Bioactivation of many PAH requires metabolism by the CYP450 system. The objective of this study was to evaluate the effects of exposure of rats to AFC on the pulmonary CYP450 system. Rats were intratracheally instilled with saline, 0.1, 0.5, or 2 mg AFC for 3 consecutive days and sacrificed the following day. Total microsomal protein and CYP2Bl and CYP1A1 isozyme levels were determined. The activities associated with CYP2B1 and CYP1A1 were measured by the O-dealkylation of 7-pentoxyresorufin (7-PR) and 7-ethoxyresorufin (7-ER), respectively. AFC exposure did not cause significant changes in total microsomal protein content. CYP2B1 and CYP1A1 levels in AFC-exposed lungs were not significantly different from control as determined by Western blot analysis. However, microsomes from AFC-exposed rats exhibited a concentration- dependent increase in the activity of 7-PR and 7-ER O-dealkylase. These results demonstrate that AFC exposure did not alter total microsomal protein or CYP1A1 and CYP2B1 levels in the lung. However, AFC increased CYP2B1 and CYP1A1 activities in lung microsomes, suggesting that AFC exposure may significantly alter metabolism of PAH by the CYP450 system in the lung.
Asphalt-fumes; Fumes; Exposure-levels; Polycyclic-aromatic-hydrocarbons; Bioactivation; Laboratory-animals; Animals; Animal-studies; Pulmonary-system-disorders; Respiratory-system-disorders; Lung-disorders
Abstract; Conference/Symposia Proceedings
The FASEB Journal