|
2D - Mechanisms of Toxic Action (MO4/13) Binding of Perfluorinated Chemicals to Serum Proteins. Jones, Paul1, Wenyue, Hu1, De Coen, Wim2, Newsted, John3, Giesy, John1, 1 Michigan State University, East Lansing, MI, USA2 University of Antwerp, Antwerp, Antwerp, Belgium3 Entrix Inc., East Lansing, MI, 48864 ABSTRACT- Perfluorooctane sulfonic acid (PFOS) accumulates in the liver and blood of exposed organisms. The potential for these surfactant molecules to interfere with hormone/protein interactions in blood is of concern given the importance of these interactions. PFOS binding to serum proteins were investigated by assessing its to displace a variety of steroid hormones from specific binding proteins in the serum of birds and fishes. PFOS had only a weak ability to displace estrogen or testosterone from carp serum steroid binding proteins. Displacement of cortisone in avian sera occurred at relatively low PFOS concentrations. Corticosterone displacement potency increased with chain length, sulfonic acids were more potent than carboxylic acids. PFOS concentrations estimated to cause these effects were 320 uM or greater, equivalent to serum concentrations greater than 160 mg/l. Using mass spectrometry and direct in vitro binding assays, PFOS was demonstrated to bind strongly to bovine serum albumin (BSA) in a 1:1 stoichiometric ratio. It appears that PFOS in serum is in general bound to albumins. Concentrations of PFOS required to saturate albumin would be in excess of 50 to 100 mg/L. Based on current environmental concentrations it is unlikely, that PFOS would cause displacement of hormones from serum proteins in wildlife. Key words: protein, PFOS, endocrine disruption, methods |
