The present 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. Using female Sprague-Dawley rats, the authors 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 analysed for biomarkers. Relationships between oral dose and biomarker concentrations were assessed using linear regression. 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. The authors concluded that the findings from this study highlight the importance of careful consideration of the oral dose used in animal experiments and provides useful information in selecting doses for future studies.
Authors: Teitelbaum SL, Li Q, Lambertini L, Belpoggi F, Manservisi F, Falcioni L, Bua L, Silva MJ, Ye X, Calafat AM, Chen J. ;Full Source: Environmental Health Perspectives. 2015 Jun 5. [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][Epub ahead of print] ;[/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]