Journal Article
Paired serum and urine concentrations of biomarkers of diethyl phthalate, methyl paraben, and triclosan in rats
Teitelbaum, SL; Li, Q; Lambertini, L; Belpoggi, F; Manservisi, F; Falcioni, L; Bua, L; Silva, MJ; Ye, X; Calafat, AM; Chen, J
Environmental Health Perspectives
ISSN: 0091-6765
EISSN: 1552-9924
Public Health Services, US Dept of Health and Human Services
BACKGROUND/OBJECTIVE: This first of its kind proof of concept rodent study examines the relationship between oral doses of three widely used personal care product ingredients (diethyl phthalate (DEP), methyl paraben (MPB), triclosan) and urine and serum concentrations of their respective biomarkers.
METHODS: Using female Sprague-Dawley rats, we carried out two rounds of experiments with oral gavage doses selected in reference to EPA NOAEL: 1735 (DEP), 1050 (MPB), 50 (triclosan) mg/kg/day. Administered doses ranged from 0.005-173 mg/kg/day, 10-100,000 times below NOAEL for each chemical. Controls for MBP and triclosan experiments were animals treated with olive oil (the vehicle) only; controls for DEP serum experiments were animals treated with the lowest MBP and triclosan doses. Doses were administered for five days with five rats in each treatment group. Urine and blood serum, collected on the last day of exposure, were analyzed for biomarkers. Relationships between oral dose and biomarker concentrations were assessed using linear regression.
RESULTS: Biomarkers were detected in all control urine samples at parts-per-billion levels suggesting a low endemic environmental exposure of the three chemicals that could not be controlled even with all precaution measures undertaken. Among exposed animals, urinary concentrations of all three biomarkers were orders of magnitude higher than those in serum. A consistently positive linear relationship between oral dose and urinary concentration was observed (R(2)>0.80); the relationship was inconsistent in serum.
CONCLUSIONS: Our study highlights the importance of careful consideration of the oral dose used in animal experiments and provides useful information in selecting doses for future studies.
endocrine-disrupting chemicals; n-butyl phthalate; hplc-ms/ms method; breast-cancer; bisphenol-a; di(2-ethylhexyl) phthalate; environmental; chemicals; pubertal development; oral toxicity; human health; Environmental Sciences & Ecology; Public, Environmental & Occupational; Toxicology
