Thyroid hormone status and pituitary function in adult rats given oral doses of perfluorooctanesulfonate (PFOS)

Waterborne exposure to PFOS causes disruption of the hypothalamus–pituitary–thyroid axis in zebrafish larvae

“…Functions such as growth, reproduction, and immune regulation are at risk when stressors persist, which may be related to early life experiences to adult fitness (Flik et al, 2006). In mammals, acute and subchronic treatment with PFOS have been shown to reduce total serum THs; however, PFOS would not have an effect on the ability of the pituitary to release TSH or to respond to hypothalamic TRH (Seacat et al, 2002;Lau et al, 2003;Thibodeaux et al, 2003;Luebker et al, 2005;Chang et al, 2008).…”

“…The down-regulated TTR gene expression observed may result in a low presence of TTR mRNA translated into less TTR protein and thus increase the free TH levels induced by PFOS treatments. Chang et al (2008) demonstrated that PFOS competes in serum for binding with thyroxine, leading to hypothyroxinemia from increased turnover and elimination of thyroxine. The decreased TTR protein levels may result in increased bioavailability of endogenous THs possibly interfering with TH transport and metabolism.…”

“…For example, exposure to the chemical in utero delayed development and reduced postnatal survival and growth Thibodeaux et al, 2003;Luebker et al, 2005). In addition, PFOS exposure significantly reduced total and free THs in rats (e.g., Seacat et al, 2002;Lau et al, 2003;Thibodeaux et al, 2003;Luebker et al, 2005;Chang et al, 2008;Yu et al, 2009), suggesting interference with thyroid function. In fish, PFOS also causes reproductive and developmental toxicity in fathead minnows (Pimephales promelas) (Ankley et al, 2005).…”

Structure–activity relations in binding of perfluoroalkyl compounds to human thyroid hormone T3 receptor

“…Numerous animal experiments have shown that PFCs impaired thyroid function (Chang et al 2008;Liu et al 2011). For example, depression of serum THs levels has been reported in PFOS-exposed rats and monkeys (Lau et al 2004).…”

Binding interactions of perfluoroalkyl substances with thyroid hormone transport proteins and potential toxicological implications

“…Gutshall et al (1989) examined the displacement of radio-labeled T4 from rat albumin in vitro by PFDA, suggested that PFDA may disrupt the TH system by displacing circulating hormone from their plasma protein binding sites. Chang et al (2008) observed a decrease in total T4, a transient increase in free T4, a transient decrease in TSH in circulation, and an increase in urinary excretion of labeled tracer from radio-labeled T4 following a single dose of PFOS, suggesting that PFOS may also act TH system disruption effect by displacing THs from their binding proteins in circulation. Based on the information obtained from previous studies, it is therefore worthwhile to investigate the binding of PFASs with TH transport proteins as a potential disruption mechanism of thyroid function.…”