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United States Department of Agriculture

Agricultural Research Service

Title: Binding of 2,2',4,4',6-Pentabromodiphenyl Ether (Bde-100) And/or Its Metabolites to Mammalian Biliary Carrier Proteins

Authors
item Larsen, Gerald
item Huwe, Janice
item Low, Michael - CONCORDIA COLLEGE
item Rutherford, Drew - CONCORDIA COLLEGE
item Hakk, Heldur

Submitted to: Organohalogen Compounds
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 16, 2004
Publication Date: June 16, 2004
Citation: Larsen, G.L., Huwe, J.K., Low, M., Rutherford, D., Hakk, H. 2004. Binding of 2,2',4,4',6-pentabromodiphenyl ether (bde-100) and/or its metabolites to mammalian biliary carrier proteins. Organohalogen Compounds 66:3830-3835.

Interpretive Summary: Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in the textile and electronics industries. Five kinds of PBDEs are consistently found in the environment, but only two have been studied in mammals. One of the five, BDE-100, because of its water insolubility would be expected to be transported in mammals by carrier proteins. The purposes of the present research were to give a single oral dose of 2,2',4,4',6-pentabromodiphenyl ether (BDE-100)to male rats and measure the amount eliminated in the urine and bile, as well as characterize the nature and extent of binding to any proteins in these excreta. Daily excretion of BDE-100 or BDE-100 degradation products in urine or bile of male rats was minimal; too little was found in urine to be studied. However, 1.8% was found in the bile. A major portion (69.4%) of the 0-72h biliary BDE-100 or BDE-100 degradation products was bound to a protein. After purification, studies showed the protein had a molecular weight of 79kDa and 53.9% of the BDE-100 or BDE-100 degradation products in the bile were bound to this protein. The identity or role of this protein is not known. A significant amount (15.5%) of the biliary BDE-100 or BDE-100 degradation products were also bound to albumin, a common serum protein. The native function of the 79kDa protein, and albumin, may be affected by binding to BDE-100 or its metabolites.

Technical Abstract: Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in the textile and electronics industries. PBDE congeners consistently found in the environment are BDE-47, 99, 100, 153, and 154, and 209. Of this group, only BDE-47 and 99 have been studied in mammals. Due to the high lipophilicity of BDE-100, it would be expected to require carrier proteins for mammalian in vivo transport. The purposes of the present research were to give 2,2',4,4',6-pentabromodiphenyl ether (BDE-100)as a single oral dose to male rats and measure the amount eliminated in the urine and bile, as well as characterize the nature and extent of binding to any proteins in these excreta. Daily excretion of 14C BDE-100 in urine or bile of male rats was minimal (0-72h urinary 14C < 0.1%, 0-72h biliary 14C was 1.8%). A major portion (69.4%) of the 0-72h biliary 14C was bound to a protein because the 14C and protein co-eluted from the G-75 column. After further purification using Sephacryl S-200 a SDS-PAGE was run on the protein and MU characterization determined that the MW of the protein was 79kDa. Of the 14C in 0-72h bile 53.9% was bound to the 79kDa protein. The identity or role of this protein is not known, but additional studies indicate it is a N-terminally blocked, monomeric protein with an isoelectric point of 5.7. A significant amount (15.5%) of the biliary 14C was also bound to albumin. The native function of the 79kDa protein, and albumin, may be affected by binding to BDE-100 or its metabolites.

Last Modified: 4/18/2014
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