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  • 1
    Electronic Resource
    Electronic Resource
    Distribution and induction of cytochrome P450 1A1 in the rainbow trout brain (1994)
    Springer
    Fish physiology and biochemistry 13 (1994), S. 335-342 
    Details
    ISSN: 1573-5168
    Keywords: fish ; rainbow trout ; brain ; cytochrome P450 ; CYP1A1 ; induction ; subcellular fractions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00003438
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  • 2
    Electronic Resource
    Electronic Resource
    The cytochrome P450 system of atlantic salmon (Salmo salar): I. Basal properties and induction of P450 1A1 in liver of immature and mature fish (1991)
    Springer
    Fish physiology and biochemistry 9 (1991), S. 339-349 
    Details
    ISSN: 1573-5168
    Keywords: cytochrome P450 ; induction ; isozymes ; β-naphthoflavone ; sex ; storage ; fish ; salmo salar
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The major components of the cytochrome P450 (P450) system in liver microsomes of Atlantic salmon were studied using spectrophotometric, catalytic and immunochemical techniques. In juvenile fish sampled during the winter season, high basal activities of 7-ethoxyresorufin O-deethylase (EROD) were found. The Km for 7-ethoxyresorufin was 0.4 µM, and Vmax 1.23 nmol/min/mg protein in juvenile fish. In mature fish sampled from the same group of fish in December, EROD activity was barely detectable (20–30 pmol/min/mg protein). Treatment with the P450 1A1 inducer β-naphthoflavone (BNF) resulted in almost 2-fold induction of total P450, and 30–40-fold induction of EROD activity in immature fish. A similar fold increase was seen in mature fish. The differences in EROD activity between untreated and BNF-treated fish, was accompanied by similar differences in a P450 1A1 cross-reacting protein (Mr=58,000 D) in immunochemical studies using rabbit anti-cod P450 1A1 IgG. However, judging from these studies, the levels of P450 1A1-protein in mature salmon far exceeded those accounted for by the measured EROD activity in comparison to immature fish (both before and after BNF-treatment), indicating inhibiting effects of sex steroids on the measured activity. This effect was not seen on 7-ethoxycoumarin O-deethylase activity. A long-term storage experiment indicated that Atlantic salmon liver microsomes can be stored for 2 years at −80°C in 20% glycerol without losing more than 20–40% of its catalytic activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02265154
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  • 3
    Electronic Resource
    Electronic Resource
    Immunochemical cross-reactivity ofβ-naphthoflavone-inducible cytochrome P450 (P450IA) in liver microsomes from different fish species and rat (1991)
    Springer
    Fish physiology and biochemistry 9 (1991), S. 1-13 
    Details
    ISSN: 1573-5168
    Keywords: cytochrome P450 ; antibodies ; induction ; β-naphthoflavone (5,6-benzoflavone) ; immunochemistry ; 7-ethoxyresorufin O-deethylase ; fish liver microsomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Antibodies prepared against the major β-naphthoflavone (BNF)-inducible cytochrome P450 (P450) forms from three species of fish (rainbow trout, Atlantic cod, and scup) well separated in teleost phylogeny, were used to investigate the immunochemical relatedness of liver microsomal P450 in different species of BNF-treated fish and rat. Rabbit polyclonal IgG against all three P450s and mouse monoclonal antibodies prepared against scup P450E were employed in this study. Liver microsomes were prepared from BNF-treated specimens of hagfish, herring, rainbow trout, cod, scup, perch, plaice and rat. With Western blotting it was shown that the various antibodies cross-reacted with a protein band in liver microsomes in the P450-region of each of the BNF-treated fish species. The apparent molecular weight of the cross-reacting proteins showed differences within the range 54,000–59,000 daltons. The effects of the different antibodies on the microsomal BNF-inducible 7-ethoxyresorufin O-deethylase (EROD) activity gave inhibition patterns that reflected to a certain extent the phylogenetic relationship of the species investigated. In rat microsomes a protein band of relative molecular mass similar to rat P450c (Mr=54,000) was recognized by all antibodies. In addition, a second band of lower molecular mass was strongly recognized by anti-cod P450c antibodies, and faintly stained with anti-rainbow trout P450LM4b IgG and anti-scup P450E MAb 1-12-3. This band could correspond to rat P450d, the isosafrole-inducible rat isoenzyme. Considering the long separate evolutionary history of some of these fishes (50–200 million years), the results demonstrate that certain antigenic epitopes in the BNF-inducible P450 isoenzymes have been strongly conserved during the evolution of fish species. These conserved epitopes seem however not to be directly involved in the measured EROD activities. Furthermore, the results suggest that the BNF-inducible P450s in fish contain regions with structural similarity to the homologous counterpart that has evolved through gene duplication into a P450 family in mammals containing at least two gene products (the P450IA gene family).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01987606
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    Paper (German National Licenses)
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