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-dimethylimid
azo[4,5-f]quinoline (MeIQ), a CYP1A2-preferential activity, was catalyzed b
y the lung S-9 fractions also. Two major bands were detected in the whole h
omogenate by western blot analysis using CD3, a mouse anti rat CYP1A1 monoc
lonal that cross-reacts with rat CYP1A2 as well as with human CYP1A1 and CY
P1A2. 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 as
say. Our findings are in agreement with the known presence of CYP1A1 in the
human lung, and provide strong evidence for the expression of catalyticall
y functional CYP1A2 in the tissue. (C) 2001 Elsevier Science Ireland Ltd. A
ll rights reserved.