Debromination of polybrominated diphenyl ether-99 (BDE-99) in carp (Cyprinus carpio) microflora and microsomes.
Based on previous findings in dietary studies with carp (Cyprinus carpio), we investigated the mechanism of 2,2',4,4',5-pentabromodiphenyl ether (BDE-99) debromination to 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) using liver and intestinal components. In vitro aerobic and anaerobic experiments tested the ability of carp intestinal microflora to debrominate BDE-99. No debromination of BDE-99 to BDE-47 was observed in microfloral samples; therefore, carp enzymatic pathways were assessed for debromination ability. After sixty-min incubation, intestine and liver microsomes exhibited 83+/-34% and 106+/-18% conversions, respectively, of BDE-99 to BDE-47; with no significant (p>0.05) difference between organ debromination capabilities. Microsomal incubations with BDE-99, enzyme cofactors and competing substrates assessed the potential mechanisms of debromination. The presence of NADPH in the microsomal assay did not significantly (p>0.05) affect BDE-99 debromination, which suggest that cytochrome P450 enzymes are not the main debrominating pathway for BDE-99. Co-incubation of BDE-99 spiked microsomes with reverse thyronine (rT3) significantly (p<0.05) decreased the debromination capacity of intestinal microsomes indicating the potential of catalytic mediation via thyroid hormone deiodinases. The significant findings of this study are that intestinal microflora are not responsible for BDE-99 debromination, however, it is an endogenous process which occurs with approximately equal activity in intestine and liver microsomes and it can be inhibited by rT3.
Duke Scholars
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Related Subject Headings
- Water Pollutants, Chemical
- Phenyl Ethers
- Microsomes
- Meteorology & Atmospheric Sciences
- Intestines
- Inactivation, Metabolic
- Halogenated Diphenyl Ethers
- Environmental Sciences
- Carps
- Animals
Citation
Published In
DOI
EISSN
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Water Pollutants, Chemical
- Phenyl Ethers
- Microsomes
- Meteorology & Atmospheric Sciences
- Intestines
- Inactivation, Metabolic
- Halogenated Diphenyl Ethers
- Environmental Sciences
- Carps
- Animals