CYP1A2 is expressed along with CYP1A1 in the human lung

The expression and activity of CYP1A1 were examined in fresh, small-sized l ung biopsy specimens from nine human subjects. CYP1A1 transcripts were dete cted by reverse transcription-polymerase chain reaction (RT PCR) analysis o f total lung RNA. CYP1A2 transcripts were detected in the RNA samples as we ll, and bioactivation of 2-aminofluorene: (2-AF) or 2-amino-3,4-dimethylimi dazo[4.5-f]quinoline (MelQ), a CYP1A2-preferential activity, was catalyzed by the lung S-9 fractions also. Two major bands were detected in the whole homogenate by western blot analysis using CD3, a mouse anti rat CYP1A1 mono clonal that cross-reacts with rat CYP1A2 as well as with human CYP1A1 and C YP1A2. S-9 fractions from the tissues catalyzed the bioactivation of benzo[ a]pyrene (B[a]P). a CYP1A1-preferential activity, to mutagens in the Ames a ssay. Our findings are in agreement with the known presence of CYP1A1 in th e human lung. and provide strong evidence for the expression of catalytical ly functional CYP1A2 in the tissue. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.