Content area
Full text
BACKGROUND: Bisphenol AF has been acknowledged to be useful for the production of CFr containing polymers with improved chemical, ihermal. and mechanical properties. Because of the lack of adequate toxicity data, bisphenol AF has been nominated for comprehensive toxicological characterization.
OBJECTIVES: We aimed to determine the relative preference of bisphenol AF for the human nuclear estrogenic receptors ERα and ERβ and the bisphenol A-specific estrogen-related receptor ERRγ, and to clarify structural characteristics of receptors that influence bisphenol AF binding.
METHODS: We examined receptor-binding activities of bisphenol AF relative to [^sup 3^H]17β-estradiol (for ERα and ERβ) and pHJbisphenol A (for ERRγ). Functional luciferase reporter gene assays were performed to assess receptor activation in HeEa cells.
RESULTS: We found that bisphenol AE strongly and selectively binds to ERs over ERRγ. Furthermore, bisphenol AF receptor-binding activity was three times stronger for ERβ [IC^sub 50^ (median inhibitory concentration) = 18.9 nM] than for ERα. When examined using a reporter gene assay, bisphenol AF was a full agonist for ERα. In contrast, it was almost completely inactive in stimulating die basal constitutive activity of ERβ. Surprisingly, bisphenol AF acted as a distinct and strong antagonist against the activity of the endogenous ERβ agonist 17β-estradiol.
CONCLUSION: Our results suggest that bisphenol AF could (unction as an endocrine-disrupting chemical bv acting as an agonist or antagonist to perturb physiological processes mediated through ERα and/or ERβ.
KEY WORDS: bisphenol A, bisphenol AF, endocrine disruptor, estrogen receptors, receptor antagonist, receptor binding. Environ Health Perspect 118:1267-1272 (2010). doi: 10.1289/ehp.0901819 [Online 28 April 2010]
Bisphenol AF (also referred to as hexafiuorobisphenol A) is a homolog of bisphenol A (BPA) (Figure 1). Bisphenol AF has a symmetrical chemical structure of HO-C^sub 6^H^sub 4^C(CF^sub 3^)^sub 2^-C^sub 6^H^sub 4^-OH and is designated as 1 . K 1 .3,3.3-hexafluoro-2,2-bis(4-hydroxyphenyl)propane by IUPAC (International Union of Pure and Applied Chemistry) nomenclature. Bisphenol AF-containing polymers such as polycarbonate copolymers, polyimides, polyamides, and polyesters arc used in high-temperature composites, electronic materials, and gas-permeable membranes. Bisphenol AF is also used in many other specialty polymer applications, including plastic optical fibers and waveguides. Although industrial production of bisphenol AF seems to be increasing considerably, no data are available on annual production or concentrations of bisphenol AF in environmental substrates.
In 2008, the U.S. National...