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2,2",4,4"-TETRABROMODIPHENYL (PBDE 47) ALTERS THYROID FUNCTION IN THE RAT.
Citation:
Hedge, J M., S C. Laws, M J. DeVito, D. Ross, K M. Crofton, AND P. C. Das. 2,2",4,4"-TETRABROMODIPHENYL (PBDE 47) ALTERS THYROID FUNCTION IN THE RAT. Presented at Society of Toxicology, Baltimore, MD, March 21-25, 2004.
Description:
Two commercial PBDE mixtures, DE-71 and DE-79, cause dose-dependent depletion of serum T4 via induction of UGTs and increased CYP1A1 activity. This work characterized the effect of a major congener, PBDE-47, in DE-71 for effects on hepatic enzymes and thyroid hormones. Female 27 day-old LE rats (n=8-14/group) were gavaged with 0, 0.3, 1, 3, 10, 30, 100 mg/kg bw PBDE-47 for 4 days. An additional group was treated with 30 mg/kg/day DE-71 (n=12) as a comparative control. Serum and liver tissues were collected on the 5th day. Serum total T4, T3, and TSH were assayed by RIA, and hepatic microsomal EROD, PROD, and UDPGT enzyme activities were determined. PBDE-47 dose-dependently decreased serum total T3 and T4 (~25%, and ~75% at the highest dose), and failed to alter TSH concentration. DE-71 was slightly more potent (10-15%) compared to the same dose of PBDE-47. These data clearly demonstrate the PBDE-47 is a thyroid hormone disrupter. This is an abstract of a proposed presentation and does not necessarily reflect U.S.EPA policy.