A simple and rapid matrix-assisted laser desorption/ionization time of flight mass spectrometry method to screen fish plasma samples for estrogen-responsive biomarkers

作者：Salinas Kimberly A^*; Hemmer Michael J; Harris Peggy S; Walker Calvin C

来源：Environmental Toxicology and Chemistry, 2008, 27(5): 1175-1183.

DOI：10.1897/07-226.1

• endocrine-disrupting compounds
• protein profiling
• matrix-assisted laser desorption/ionization
• sheepshead minnow
• estrogen

In the present study, we describe and evaluate the performance of a simple and rapid mass spectral method for screening fish plasma for estrogen-responsive biomarkers using matrix-assisted laser desorption/ionization (MALDI) time of flight mass spectrometry coupled with a short-term fish assay. Adult male sheepshead minnows (Cyprinodon variegatus) were placed into aquaria consisting of vehicle control and the following estrogen agonist treatments: 17 beta-estradiol (0.00625, 0.0125, 0.025, 0.05, 0.1, 0.2, 0.5, and 1.0 mu g/L, 4-tert-pentylphenol (100 mu g/L), methoxychlor (6 and 12 mu g/L), and bisphenol A (100 and 1,000 mu g/L). Treatments with chlorpyrifos (80 mu g/L) and endosulfan (0.6 mu g/L) served as nonestrogenic negative controls. Test concentrations were maintained using an intermittent flow-through dosing apparatus. Plasma was obtained from individuals, diluted and applied to an inert surface, and analyzed by MALDI. Multiple protein peaks, ranging from 2.9 to 12.9 kDa, were identified as markers of estrogenic effects when comparing estrogen-treated and control fish using interpercentile reference values. A binary classification tree model was constructed from plasma protein profiles of the vehicle control and the 0.2 mu g/L of 17 beta-estradiol treatments and then used to evaluate all samples. Treatments with the estrogen agonists 17 beta-estradiol, 4-tert-pentyl phenol, methoxychlor, and bisphenol-A generated reproducible diagnostic biomarkers based on the presence of specific estrogen-responsive plasma proteins. The controls and nonestrogenic compounds chlorpyrifos and endosulfan did not produce this estrogen-responsive protein profile. A no-observed-effect level for 17 beta-estradiol at 0.025 mu g/L was estimated from concentration-response exposures. The MALDI method described here provides a straightforward, sensitive, and specific tool to screen chemicals for estrogenic activity.

• 出版日期2008-5