Studies have shown that debromination of the major component in the deca-brominated diphenyl ether mixture (deca-BDE), BDE-209, occurs in vivo in birds. Recent work from our laboratory on breeding ring-billed gulls (Larus delawarensis) exposed to elevated PBDE concentrations in the densely-populated metropolis of Montreal (Canada) further suggests that BDE-209 debromination is potentially catalyzed by deiodinases in liver microsomes. The first objective of this study was to determine if type 1 deiodinase (D1) was involved in the in vitro debromination of BDE-209 in liver microsomes of ring-billed gulls. The second objective was to determine if there was an interaction between D1 and BDE-209 using an in vitro D1 activity assay. No depletion of BDE-209 was observed in gull liver microsomes. A significant 42% increase in total D1 activity was found in gull liver microsomes at the medium BDE-209 concentration (1.0 nM), although not at the low (0.5 nM) or high (2.5 nM) concentrations, suggesting potential non-dose related interaction with D1. Moreover, no correlation was found between total D1 activity in liver microsomes and plasma thyroid hormone levels, although there was a negative relationship between plasma BDE-209 concentrations and FT₃ levels. Results from this study suggest that debromination of BDE-209 did not occur using present in vitro assay conditions, although indicated potential interaction with D1 that may have implication on circulating thyroid hormone status.

研究表明，十溴代二苯醚混合物（deca-BDE）BDE-209中的主要成分在体内发生脱溴。我们实验室最近对在蒙特利尔（加拿大）人口稠密的大都市中暴露于高浓度PBDE浓度的环状带嘴鸥（Larus delawarensis）的研究进一步表明，BDE-209脱溴作用可能是由肝微粒体中的脱碘酶催化的。这项研究的第一个目的是确定1型脱碘酶（D1）是否参与了环鸥肝微粒体中BDE-209的体外脱溴处理。第二个目标是使用体外方法确定D1和BDE-209之间是否存在相互作用D1活性测定。在鸥肝微粒体中未观察到BDE-209的消耗。在中度BDE-209浓度（1.0 nM）下，鸥肝微粒体的总D1活性显着增加了42％，尽管在低浓度（0.5 nM）或高浓度（2.5 nM）并非如此，表明潜在的非剂量相关性与D1的互动。此外，尽管血浆BDE-209浓度与FT ₃水平呈负相关，但在肝微粒体中总D1活性与血浆甲状腺激素水平之间没有相关性。这项研究的结果表明，尽管显示了与D1的潜在相互作用，可能与循环甲状腺激素状态有关，但在目前的体外测定条件下并未发生BDE-209的脱溴。