Distribution and induction of cytochrome P450 1A1 in the rainbow trout brain |
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Authors: | Tommy Andersson Anders Goksøyr |
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Institution: | 1. Department of Zoophysiology, University of G?teborg, Box 25059, 400 31, G?teborg, Sweden 2. Laboratory of Marine Molecular Biology, University of Bergen, HIB, N-5020, Bergen, Norway
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Abstract: | Cytochrome P450 (CYP) 1A1 participates in the activation as well as detoxification of environmental pollutants such as aromatic
hydrocarbons. This CYP form is also efficiently induced by aromatic hydrocarbons. The presence of CYP 1A1 in the brain might
thus be of physiological and toxicological importance. In the present investigation on rainbow trout, the distribution of
7-ethoxyresorufin-O-deethylase (EROD) activity, a cytochrome CYP 1A1 catalyzed reaction, was measured in whole tissue homogenates
from brain parts. In control fish, a relatively high activity was found in the rainbow trout olfactory bulb compared to the
other brain parts. Although an EROD induction (3 to 7-fold) by β-naphthoflavone (BNF) was recorded in all brain parts from
the rainbow trout, the highest induced activity was measured in the olfactory bulbs. To ascertain the distribution of EROD
activity in cells, whole brain tissue was subfractionated by differential centrifugation. The fractionation scheme separated
mitochondria (P2 fraction) and microsomes (P3 fraction) as determined by marker enzymes and electron microscopy. In control
rainbow trout, a low EROD activity could be measured in the P2 fraction. BNF induced the EROD activity in both P2 and P3 fractions.
Western blotting showed the induction by BNF of a protein band in the P2 and P3 fractions with a molecular mass around 58,000
when highly specific anti-cod CYP 1A1 antibodies were used. ELISA measurements confirmed the induction of CYP 1A1 protein
in the rainbow trout brain subcellular fractions. |
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Keywords: | fish rainbow trout brain cytochrome P450 CYP1A1 induction subcellular fractions |
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