PBDE flame retardants: Toxicokinetics and thyroid hormone endocrine disruption in fish
Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardant chemicals that have been used in large quantities and are now detected worldwide in humans and wildlife. To complement reviews of effects on human health, this review discusses and synthesizes current evidence of PBDE toxicokinetics and toxicity mechanisms leading to perturbations of thyroid hormone homeostasis in fish. PBDE disruptions to thyroid signaling in fish appear to proceed through multiple pathways involving declines in circulating thyroid hormones, disrupted deiodination activity, hindered hormone transport, and altered transcriptional regulation of genes involved in thyroid hormone production, transport, and genomic signaling. PBDE exposures have also been linked to impacts on reproductive health with reductions in fecundity, spawning, hatching success, and offspring survival observed in some species, as well as impaired fertility. These studies on PBDE mediated hormone disruption in fish can help inform future studies seeking to understand potential developmental effects in humans.