In vitro and in vivo interactions of organohalogens with the endocrine system : the role of metabolites and implications for human health

Organohalogen compounds such as polychlorinated biphenyls (PCBs) belong to the group of persistent compounds, implying that they are slowly biodegradable and accumulate in the environment. A new group of possibly persistent compounds are the polybrominated diphenyl ethers (PBDEs). These PBDEs have recently been identified in the environment, and their toxicity is relatively unknown. PBDEs are used extensively as flame retardants in e.g. computers, tv-sets, or textile. In this thesis, the toxicity of PBDEs is described.<br/>In vitro experiments revealed that PBDEs are able to bind to transthyretin (TTR), a thyroid hormone transport protein, and can exert estrogenic activity. In vivo experiments with a model compound showed that these substances can have adverse effects on brain development and the estrous cycle in offspring of rats exposed in utero.<br/>The concentrations that gave rise to these effects in the rats are only one order of magnitude higher than the concentrations in which these compounds are currently present in human blood.