Differential inhibition of hepatic microsomal alkoxyresorufin O-dealkylation activities by tetrachlorobiphenyls

Edwards, Patrick R.; Hrycay, Eugene G.; Bandiera, Stelvio M.

doi:10.1016/j.cbi.2007.05.004

Cited by 13 publications

(10 citation statements)

References 26 publications

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“…Rats were housed as previously described [15] and cared for in accordance with the principles and guidelines of the Canadian Council on Animal Care. Liver microsomes were prepared from pooled liver homogenates as reported previously [16] and aliquots were stored at −80 • C. Protein concentration was measured by the method of Lowry et al [17] using bovine serum albumin as a standard.…”

Section: Animal Treatment and Preparation Of Hepatic Microsomesmentioning

confidence: 99%

Validation of a novel in vitro assay using ultra performance liquid chromatography–mass spectrometry (UPLC/MS) to detect and quantify hydroxylated metabolites of BDE-99 in rat liver microsomes

Erratico

Szeitz

Bandiera

2010

Journal of Chromatography B

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Section: Animal Treatment and Preparation Of Hepatic Microsomesmentioning

confidence: 99%

Validation of a novel in vitro assay using ultra performance liquid chromatography–mass spectrometry (UPLC/MS) to detect and quantify hydroxylated metabolites of BDE-99 in rat liver microsomes

Erratico

Szeitz

Bandiera

2010

Journal of Chromatography B

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“…The presence of higher concentrations of PCBs that induce the enzymes responsible for the hyper or accelerated induction activities was deemed an unlikely explanation given the lower levels of total PCBs and all individually eluting PCB fractions. Lower levels of PCBs could account for apparent hyper induction since it has been shown that tetrachlorobiphenyls can inhibit rat microsomal alkoxyresorufin dealkylase activities [25]. However the dealkylase inhibition profile of tetrachlorobiphenyls based on planarity would pair EROD with MROD activities and separate BROD activity, rather than the pairing of MROD and BROD and separation of EROD activity shown in the present study.…”

Section: Discussionmentioning

confidence: 54%

Hyper- and hypo-induction of cytochrome P450 activities with Aroclor 1254 and 3-methylcholanthrene in Cyp1a2(−/−) mice

Barker

Hathaway

Arch

et al. 2009

Chemico-Biological Interactions

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The response of hepatic mono-oxygenase activities to Aroclor 1254 or 3-methylcholanthrene was investigated in wild-type and Cyp1a2(−/−) mice. Cytochrome P450 concentrations were similar in naïve Cyp1a2(−/−) and wild-type mice. There was no difference between naïve wild-type and Cyp1a2(−/−) animals in 7-ethoxyresorufin and 7-ethoxy-4-trifluoromethylcoumarin dealkylase activities, nor was the induction response after 3-methylcholanthrene any different between the two genotypes. However, both activities were induced to a higher extent in Cyp1a2(−/−) mice after Aroclor 1254. In contrast, 7-pentoxyresorufin dealkylation activity was lower in Cyp1a2(−/−) mice and this differential was maintained during induction by both agents. 7-Methoxy- and 7-benzoxyresorufin dealkylation activities were also lower than wild-type in naïve Cyp1a2(−/−) animals and during 3-methylcholanthrene induction, but showed accelerated induction in Cyp1a2(−/−) mice with Aroclor 1254. Bufuralol 1′- and testosterone 6β-hydroxylation activities, and P450 characteristics were evaluated 48 hours after inducer administration. Bufuralol 1′-hydroxylation, a sexual dimorphic activity (female > male) showed no genotype differences in naïve animals. Activity changes varied across gender and genotype, with 3-methylcholanthrene and Aroclor 1254 inducing in male Cyp1a2(−/−), and Aroclor 1254 inducing in female wild-type. Testosterone 6β-hydroxylation activity was 16% higher in Cyp1a2(−/−) mice and neither 3-methylcholanthrene nor Aroclor 1254 elicited induction. After Aroclor 1254, a 24% increase in P450 concentration with a hypsochromic shift in the ferrous-CO maximum characteristic of CYP1A enzymes occurred in wild-type, compared to no change in either parameter in Cyp1a2(−/−) mice. Induction changes with 3-methylcholanthrene were greater in wild-type mice, a 60% increase in concentration and ~2 nm hypsochromic shift versus a 10% increase and ~1 nm hypsochromic shift in Cyp1a2(−/−) mice. The study demonstrates that deletion of a single P450 can profoundly affect the induction response, as monitored with activities of other P450s, in a manner unrelated to the contribution of the deleted P450 to the activity.

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“…Another important issue that has to be considered here is the fact that certain ubiquitous contaminants as pharmaceuticals (diclofenac, carbamazepine, clofibrate etc. ), organochlorine residues and some metallic contaminants (organotins, mercury) were proven to inhibit the CYP-like enzymes and associated mixed function oxidase components (Thibaut et al, 2006;Lavado et al, 2006;Edwards et al, 2007;Faria et al, 2010) in several biological models. Thus, for sites as harbours, which are usually affected by complex mixtures of contaminants, the antagonism of chemicals on the EROD activity of aquatic biota might also be expected.…”

Section: Discussionmentioning

confidence: 99%

Interspecies comparison of selected pollution biomarkers in dreissenid spp. inhabiting pristine and moderately polluted sites

Farkas

Ács

Vehovszky

et al. 2017

Science of The Total Environment

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Stress biomarkers, which can outline impacts of contaminants in aquatic biota at the biochemical level, are increasingly used as early warning tools in environmental monitoring. Reliable biomarker based assessment schemes, however, request appropriate knowledge of baseline levels of selected endpoints, and the potential influence of a range of natural influencing factors (both abiotic and biotic) as well. In this study, we examined the interspecies variability of various biomarkers (metallothioneins (MT), ethoxyresorufin-Odeethylase activity (EROD), lipid peroxidation (LPO), DNA strand breaks (DNA_sb), vitellogenin-like proteins (Vtg)) in Dreissena polymorpha and Dreissena bugensis inhabiting either pristine-or moderately impacted sites of Lake Balaton (Hungary). Levels of all biomarkers considered revealed low interspecies variability in the two dreissenid species at all sampling sites, with consistently higher (but statistically insignificant) values in Dreissena polymorpha. Levels of all biomarkers varied within the two investigated seasons, with significant influence of the reproduction cycle particularly on the levels of metallothioneins and vitellogenin-like proteins. Each biomarker considered was elevated by October, with significantly higher values in the mussels inhabiting harbours. Insignificant spatial and temporal variability in the general health indicators (condition index, total protein content) of dreissenids was observed, which, in parallel with evident rise in biomarker levels, apparently suggest that the anthropogenic impacts in harbours affect mussel fitness yet at sub organismal level. Our data might serve useful basis for future environmental monitoring surveys, especially in habitats where the progressive replacement of Dreissena polymorpha by Dreissena bugensis is taking place, as the interspecies variability in susceptibility to chemical stress of the two species is well comparable.

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Differential inhibition of hepatic microsomal alkoxyresorufin O-dealkylation activities by tetrachlorobiphenyls

Cited by 13 publications

References 26 publications

Validation of a novel in vitro assay using ultra performance liquid chromatography–mass spectrometry (UPLC/MS) to detect and quantify hydroxylated metabolites of BDE-99 in rat liver microsomes

Validation of a novel in vitro assay using ultra performance liquid chromatography–mass spectrometry (UPLC/MS) to detect and quantify hydroxylated metabolites of BDE-99 in rat liver microsomes

Hyper- and hypo-induction of cytochrome P450 activities with Aroclor 1254 and 3-methylcholanthrene in Cyp1a2(−/−) mice

Interspecies comparison of selected pollution biomarkers in dreissenid spp. inhabiting pristine and moderately polluted sites

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