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  • 1
    Electronic Resource
    Electronic Resource
    Response of xenobiotic metabolizing enzymes of rainbow trout (Oncorhynchus mykiss) to the mono-ortho substituted polychlorinated PCB congener 2,3′,4,4′,5-pentachlorobiphenyl, PCB-118, detected by enzyme activities and immunochemical methods (1991)
    Springer
    Archives of environmental contamination and toxicology 20 (1991), S. 349-352 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract The rnono-ortho-substituted polychlorinated PCB congener 2,3′,4,4′,5′-pentachlorobiphenyl (PCB-118) was administered i.p. (30 mg/kg body weight) to gonadally immature rainbow trout (Oncorhynchus mykiss), of both sexes. In liver microsomes prepared from fish killed 4 days after administration, the cytochrome P450-dependent monooxygenase activities of 7-ethoxyresorufin O-deethylase (EROD), aryl hydrocarbon hydroxylase (AHH), and aldrin epoxidase (AE) were measured. In addition, NADPH-cytochrome c reductase (NCCR) was analyzed, and the content of a specific cytochrome P450 isozyme was determined with Western blotting and an enzyme-linked immunosorbent assay (ELISA) using rabbit anticod P450IA1 IgG. The monooxygenase parameters EROD and AHH were significantly induced to 558 and 268%, respectively, of the corresponding control values, while NCCR and AE activities were not affected. The antibodies to cod P450IA1 recognized a single protein band (Mr = 58 000 D) in the rainbow trout liver microsomes. The ELISA absorbance of this protein in the PCB-118 treated fish was 401% of the corresponding value in the controls. These results demonstrate that PCB-118 is an effective inducer of the subfamily cytochrome P450IA1 in rainbow trout liver microsomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01064401
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  • 2
    Electronic Resource
    Electronic Resource
    Environmental contaminants and biochemical responses in flatfish from the Hvaler Archipelago in Norway (1991)
    Springer
    Archives of environmental contamination and toxicology 21 (1991), S. 486-496 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract The levels of several environmental contaminants, including selected polyaromatic hydrocarbons (PAH), organochlorines (DDT/DDE, hexachlorobenzene), 15 polychlorinated biphenyl (PCB) congeners, and polychlorinated dibenzofurans and dibenzo-p-dioxins, PCDF/PCDD), and heavy metals (Cd, Hg, Pb, and As) were analyzed in muscle and liver of three different flatfish species (dab,Limanda limanda; flounder,Platichthys flesus; plaice,Pleuronectes platessa) caught by gill netting at different sites in the Hvaler Archipelago. Indices of biochemical effects in liver S9-fractions were studied by measuring cytochrome P450-dependent monooxygenase and UDP-glucuronyl transferase activities, and by immunoquantitating cytochrome P450 1A1 using an indirect enzyme-linked immunosorbent assay (ELISA). Only low levels of PCDD/PCDF, Cd, and Pb were observed, whereas PCB levels were significantly elevated in fish from the inner sites of the Archipelago compared to a reference site. The contaminant gradient toward the Glomma estuary was correlated with increased cytochrome P450 1A1 activity, measured as 7-ethoxyresorufin O-deethylase (EROD), and with immunoquantitated P450 1A1. In contrast, fish from the site at Idefjorden, although containing elevated contaminant levels, did not show elevated EROD activity, but apparently elevated P450 1A1 protein. These findings may reflect different pollution histories of the sites, and indicate the applicability of biochemical effect indices (i.e., EROD and P450 1A1 immunoquantitation) to monitoring studies. The integrated chemical-biochemical approach employed in this study can obviously be expanded to give fruitful information about cause-effect relationships in other contaminant situations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01183869
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  • 3
    Electronic Resource
    Electronic Resource
    The cytochrome P450 system of Atlantic salmon (Salmo salar): II. Variations in hepatic catalytic activities and isozyme patterns during an annual reproductive cycle (1992)
    Springer
    Fish physiology and biochemistry 10 (1992), S. 291-301 
    Details
    ISSN: 1573-5168
    Keywords: cytochrome P450 ; annual cycle ; reproduction ; sex ; enzyme activities ; fish liver microsomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A group of Atlantic salmon (Salmo salar) was followed through their first year of maturation and spawning. At monthly intervals, starting with juvenile fish in December, 5–7 fish of each sex were killed, and liver and plasma were sampled. The last sampling point was of spawning fish in November a year later. Variables in the cytochrome P450 (P450) system were studied in hepatic microsomes, and estradiol 17β was measured in the plasma of females to assess the maturational status. The P450 1A1-mediated 7-ethoxyresorufin O-deethylase (EROD) started at high levels in winter, but decreased to non-detectable activities in pre-spawning females. Decreases, but not to the same extent, were also observed during this period in total cytochrome P450, cytochrome b5, NADPH-cytochrome P450 reductase, and in the content of two immunochemically determined P450 isozymes. At the same time, LSI levels increased in maturing females (starting in July), and GSI levels increased in both sexes (starting in May). Sex specific differences were observed in pre-spawning fish in September and October, with levels of total P450, b5, NADPH-cytochrome P450 reductase, EROD and P450 isozymes significantly lower in females. At the same time, plasma estradiol-17β levels reached peak values in females. The results point to the important role of sex steroids such as estradiol-17β as major factors in the regulation of final sexual maturation. However, this study also indicates that there may be estradiol-17β independent events of equal importance in the early stages of gonadal maturation that may involve the P450 system. The changes observed in the P450 system (as a major drug and steroid metabolizing system) of Atlantic salmon during sexual maturation may be of importance both in the endogenous transduction of hormonal signals, and as a pharmacological basis for designing therapeutic treatment of diseases in the aquaculture industry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00004478
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  • 4
    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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  • 5
    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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  • 6
    Electronic Resource
    Electronic Resource
    Immunochemical relationships of cytochrome P4503A-like proteins in teleost fish (1996)
    Springer
    Fish physiology and biochemistry 15 (1996), S. 323-332 
    Details
    ISSN: 1573-5168
    Keywords: cytochrome P450 ; CYP3A ; fish ; immunoblotting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Multiple P450 proteins have been purified from several teleost species, including rainbow trout (Oncorhynchus mykiss), scup (Stenotomus chrysops) and Atlantic cod (Gadus morhua). Identity, relationships and/or functions have been established in these fish species for the cytochrome P4501 As. Information about the structure, function, regulation and relationships of other piscine cytochrome P450 (CYP) proteins is sparse. In the present study we have focused on constitutively expressed CYP forms, P450con and LMC5 isolated from rainbow trout, P450A from scup, and P450b from Atlantic cod, and we consider evidence for the relationship of these proteins to mammalian members of the CYP3A subfamily. Reciprocal western blot analysis shows that P450con and LMC5, isolated from rainbow trout in two different laboratories, are closely related and ostensibly identical proteins. These trout proteins show specific reciprocal cross-reactivity with scup P450A, and polyclonal antibodies (PAb) to the trout and scup proteins both recognize cod P450b, indicating that rainbow trout P450con/LMC5, scup P450A and cod P450b are immunochemically-related proteins. In analyses of liver microsomes of trout, scup and cod, PAb to trout P450con/LMC5 and scup P450A recognize only bands that are identical in migration to the CYP proteins purified from these species, and which were used as immunogens. These CYP proteins purified from fish are each immunochemically-related to mammalian CYP3A proteins, showing recognition by PAb to human CYP3A4 and to rat CYP3A1. PAb to the mammalian CYP3As also recognize the same bands in liver microsomes from these fish species as seen by PAb to the fish proteins. These results strongly suggest that these fish proteins are members of theCYP3 gene family and probably theCYP3A subfamily. Although sequence analysis is required before their designation in the CYP3A subfamily can be confirmed and specified, we refer to these as CYP3A-like. Immunoblot analyses of hepatic microsomes from other fish species with PAb to scup P450A and trout P450con show that multiple CYP3A-like proteins are expressed in liver of several species, including killifish (Fundulus heteroclitus) and winter flounder (Pleuronectes americanus). Important questions still remain to be addressed concerning CYP3A structure, multiplicity, physiological function, regulation and metabolism of endogenous as well as exogenous substrates in fish.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02112359
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  • 7
    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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