Linked Life Data

16177242

Source:http://linkedlifedata.com/resource/pubmed/id/16177242

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2005-11-10
pubmed:databankReference
pubmed:abstractText
This study presents concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and dioxin-like coplanar PCBs (Co-PCBs) in the liver and breast muscle of jungle crows (JCs; Corvus macrorhynchos) collected from Tokyo, Japan. 2,3,7,8-Tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) derived by WHO bird-TEF were in the range of 23 to 280 pg/g (lipid) in the liver, which are lower or comparable to the lowest-observed-effect-level of CYP induction in chicken, and 5.6-78 pg/g (lipid) in the pectoral muscle. Cytochrome P450 (CYP) 1A-, 2B-, 2C-, and 3A-like proteins were detected using anti-rat CYP polyclonal antibodies in hepatic microsomal fractions. Significant (p < 0.05) positive correlations between hepatic TEQs and CYP1A or CYP3A-like protein expression levels were noticed, implying induction of these CYP isozymes by TEQs. On the other hand, there was no significant positive correlation between muscle TEQ and any one of analyzed CYP isozyme expression levels. CYP1A- and CYP3A-like protein expression levels represented better correlations with pentoxy- and benzyloxyresorufin-O-dealkylase activities rather than methoxy- and ethoxyresorufin-O-dealkylase activities, indicating unique catalytic functions of these CYPs in JCs. Furthermore, we succeeded in isolating CYP1A5 cDNA from the liver of JC, having an open reading frame of 531 amino acid residues with a predicted molecular mass of 60.3 kDa. JC CYP1A5 mRNA expression measured by real-time RT-PCR had a significant positive correlation with hepatic TEQs, suggesting induction of CYP1A5 at the transcriptional level. Ratios of several Co-PCB congeners to CB-169 in the liver of JCs revealed significant negative correlations with CYP1A protein or CYP1A5 mRNA expression levels, implying metabolism of these congeners by the induced CYP1A. The liver/breast muscle concentration (L/M) ratios of PCDDs/DFs and CB-169 increased with an increase in hepatic CYP1A protein or CYP1A5 mRNA expression levels, suggesting congener-specific hepatic sequestrations by the induced CYP1A. The present study provides insights into the propensity of CYP1A induction to the exposure of dioxin-like chemicals, and unique metabolic and sequestration capacities of CYP1A in JC.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1096-6080
pubmed:author
pubmed:issnType
Print
pubmed:volume
88
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
384-99
pubmed:dateRevised
2010-9-17
pubmed:meshHeading
pubmed-meshheading:16177242-Amino Acid Sequence, pubmed-meshheading:16177242-Animals, pubmed-meshheading:16177242-Aryl Hydrocarbon Hydroxylases, pubmed-meshheading:16177242-Base Sequence, pubmed-meshheading:16177242-Benzofurans, pubmed-meshheading:16177242-Crows, pubmed-meshheading:16177242-Dioxins, pubmed-meshheading:16177242-Enzyme Induction, pubmed-meshheading:16177242-Gene Expression, pubmed-meshheading:16177242-Liver, pubmed-meshheading:16177242-Male, pubmed-meshheading:16177242-Microsomes, Liver, pubmed-meshheading:16177242-Molecular Sequence Data, pubmed-meshheading:16177242-Muscle, Skeletal, pubmed-meshheading:16177242-Oxidoreductases, pubmed-meshheading:16177242-Polychlorinated Biphenyls, pubmed-meshheading:16177242-RNA, Messenger, pubmed-meshheading:16177242-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:16177242-Tetrachlorodibenzodioxin, pubmed-meshheading:16177242-Transcription, Genetic
pubmed:year
2005
pubmed:articleTitle
Induction of cytochrome P450 1A5 mRNA, protein and enzymatic activities by dioxin-like compounds, and congener-specific metabolism and sequestration in the liver of wild jungle crow (Corvus macrorhynchos) from Tokyo, Japan.
pubmed:affiliation
Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't