PBBs endocrine effects

Polybrominated Diphenyl Ethers. There is suggestive evidence of hypothyroidism in a small group of workers who were occupationally exposed to decaBDE as well as PBBs (Bahn et al. 1980), as summarized in the preceding subsection on endocrine effects of PBBs. 

Polybrominated Biphenyls. No studies were located regarding endocrine effects in humans after oral exposure to PBBs. 

No studies were located regarding the mechanism of endocrine effects (thyroid toxicity, estrogenicity) of PBBs. 

A potential biomarker of exposure to PBBs is related to their effect on the thyroid gland. As discussed in Sections 3.2.2.2, Endocrine Effects, the thyroid gland is an unequivocal target of PBBs in animals, and evidence in humans is suggestive of a similar relationship. Effects in workers exposed to unspecified PBBs and/or decabromobiphenyl included increased scrum thyrotropin, low or borderline low serum T4, and increased thyroid antimicrosomal antibody titers (Bahn et al. 1980). A spectrum of thyroid effects has been... 

Polybrominated Biphenyls. PBBs have the potential to interact with the endocrine system based on effects that mainly include changes in levels of thyroid and female reproductive hormones. No studies were located that investigated the estrogenic and antiestrogenic activity of PBBs in vitro or in vivo at the level of the estrogen receptor. 

Brominated flame retardants are widely used as polymer additives in plastics, electric appliances, and textile and polyurethane foams. Some of the technical flame retardant products contain brominated organic compounds, including polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers. These compounds are structurally similar to PCBs and, therefore, their chemical properties, persistence, bioaccumulation, and distribution in the environment follow similar patterns. Moreover, they have potential endocrine disrupting properties and there are concerns over their exposure health effects. 

Several studies in the older literature address effects of Pb on calcitropic endocrine functions in humans. Earlier discussion addressed effects of Pb on children s l,25-(OH)2-D3 levels, where relatively high PbB concentrations in children (>30 p.g/dl) depressed vitamin D levels. Calcium repletion even in the presence of elevated PbB values appears to abolish the reduction. Mixed results for levels of parathyroid hormone (PTH), calcitonin (CAL), l,25-(OH)2-D3, and 25-hydroxy vitamin D (25-OH-D3) have been noted for lead workers with high PbB values compared to adults in the general population. Kristal-Boneh et al. (1998) saw increases in the two hormones reported, serum PTH and 1,25-(0H)2-D, with increasing PbB (mean = 43 p.g/dl). Mason et al. (1990), by contrast, saw an increase in the dihydroxy vitamin D but no change in 25-OH-D3. 

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