PMID- 22074031
OWN - NLM
STAT- MEDLINE
DCOM- 20120508
LR  - 20120113
IS  - 1520-5851 (Electronic)
IS  - 0013-936X (Linking)
VI  - 46
IP  - 1
DP  - 2012 Jan 3
TI  - In vitro transactivation potencies of black-footed albatross (Phoebastria 
      nigripes) AHR1 and AHR2 by dioxins to predict CYP1A expression in the wild 
      population.
PG  - 525-33
LID - 10.1021/es2028263 [doi]
AB  - Our previous studies have detected high levels of dioxins and related compounds 
      (DRCs) including polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs), and 
      coplanar PCBs (Co-PCBs) in the black-footed albatross (BFA), Phoebastria 
      nigripes, from the North Pacific region. We have also cloned two aryl hydrocarbon 
      receptors, AHR1 and AHR2, of the BFA. To evaluate the sensitivity to DRCs in the 
      BFA and to assess the status of cytochrome P450 1A (CYP1A) induction in the wild 
      population, this study investigated the mRNA expression levels of BFA AHR1 and 
      AHR2 and also the transactivation potencies of each AHR by 15 selected DRC 
      congeners. Quantitative real-time PCR of BFA AHR mRNAs showed that hepatic AHR1 
      is more highly expressed than AHR2. Transactivation by graded concentrations of 
      individual DRCs was measured in COS-7 cells, where BFA AHR1 or AHR2 was 
      transiently transfected. For congeners that exhibited AHR-mediated dose-dependent 
      activities, 50% effective concentration (EC(50)) and 
      2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) relative potencies (REPs) were 
      estimated. Based on the estimates of the REPs, TCDD induction equivalency factors 
      (IEFs) were determined. For BFA AHR1, PeCDF was equipotent to TCDD, but other 
      congeners exhibited lower IEFs. For BFA AHR2, PCDD/F congeners except OCDD/F 
      showed IEFs >/= 1.0. Using BFA AHR1- or AHR2-IEFs and hepatic concentrations of 
      DRCs in North Pacific BFAs, TCDD induction equivalents (IEQs) were calculated. We 
      further constructed nonlinear regression models on the relationships between BFA 
      AHR1- or AHR2-IEF derived total IEQ or WHO-TEF derived total TEQ and 
      ethoxyresorufin-O-deethylase activity (EROD) in the liver of wild BFAs. The 
      results indicated that the relationships of BFA AHR1- and AHR2-based IEQs and 
      EROD were predictable from BFA AHR1- and AHR2-mediated transactivation by TCDD, 
      respectively. Collectively, these results suggest that the in vitro assay 
      incorporating the AHR of species of concern would be a useful tool to predict the 
      sensitivity to DRCs in the species and CYP1A induction in the wild population.
FAU - Mol, Thuruthippallil Leena
AU  - Mol TL
AD  - Center for Marine Environmental Studies, Ehime University, Bunkyo-cho 2-5, 
      Matsuyama 790-8577, Japan.
FAU - Kim, Eun-Young
AU  - Kim EY
FAU - Ishibashi, Hiroshi
AU  - Ishibashi H
FAU - Iwata, Hisato
AU  - Iwata H
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20111130
PL  - United States
TA  - Environ Sci Technol
JT  - Environmental science & technology
JID - 0213155
RN  - 0 (Amino Acids)
RN  - 0 (Dioxins)
RN  - 0 (Receptors, Aryl Hydrocarbon)
RN  - EC 1.14.14.1 (Cytochrome P-450 CYP1A1)
SB  - IM
MH  - Amino Acids/metabolism
MH  - Animals
MH  - Animals, Wild/*genetics
MH  - Birds/*genetics
MH  - Cytochrome P-450 CYP1A1/*metabolism
MH  - Dioxins/*toxicity
MH  - Gene Expression Regulation/drug effects
MH  - Liver/drug effects/enzymology
MH  - Nonlinear Dynamics
MH  - Receptors, Aryl Hydrocarbon/chemistry/*genetics/metabolism
MH  - Regression Analysis
MH  - Structure-Activity Relationship
MH  - Transcriptional Activation/*drug effects/genetics
MH  - World Health Organization
EDAT- 2011/11/15 06:00
MHDA- 2012/05/09 06:00
CRDT- 2011/11/15 06:00
PHST- 2011/11/15 06:00 [entrez]
PHST- 2011/11/15 06:00 [pubmed]
PHST- 2012/05/09 06:00 [medline]
AID - 10.1021/es2028263 [doi]
PST - ppublish
SO  - Environ Sci Technol. 2012 Jan 3;46(1):525-33. doi: 10.1021/es2028263. Epub 2011 
      Nov 30.