Disposition of 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE153) and its interaction with other polybrominated diphenyl ethers (PBDEs) in rodents.

The disposition of the 14C-labelled polybrominated diphenyl ether (PBDE) 2,2',4,4',5,5'-hexaBDE (BDE153) was investigated in rodents following single and multiple doses and in a mixture with radiolabelled 2,2',4,4'-tetraBDE (BDE47) and 2,2',4,4',5-pentaBDE (BDE99). In single exposure studies there was little or no effect of dose on BDE153 disposition in male rats in the range 1-100 micromol kg-1. No major sex or species differences in the in vivo fate of BDE153 were detected. BDE153 was absorbed in rats or mice following gavage by approximately 70%; retained in tissues; and poorly metabolized and slowly excreted. Mixture studies indicated that, relative to each other, more BDE47 was distributed to adipose tissue, more BDE153 accumulated in the liver, and BDE99 was metabolized to the greatest extent. BDE153 was probably retained in the liver due to minimal metabolism and elimination after 'first-pass' distribution to the tissue following gavage.