13 research outputs found

    Quantification of steroids and endocrine disrupting chemicals in rat ovaries by LC-MS/MS for reproductive toxicology assessment

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    International audienceReproductive function is controlled by a finely tuned balance of androgens and estrogens. Environmental toxicants, notably endocrine disrupting chemicals (EDCs), appear to be involved in the disruption of hormonal balance in several studies. To further describe the effects of selected EDCs on steroid secretion in female rats, we aim to simultaneously investigate the EDC concentration and the sex hormone balance in the ovaries. Therefore, an effective method has been developed for the quantification of the sex steroid hormones (testosterone, androstenedione, estradiol, and estrone) and four endocrine disrupting chemicals (bisphenol A, atrazine, and the active metabolites of methoxychlor and vinclozolin) in rat ovaries. The sample preparation procedure is based on the so-called "quick, easy, cheap, effective, rugged, and safe" approach, and an analytical method was developed to quantify these compounds with low detection limits by liquid chromatography coupled with a tandem mass spectrometer. This analytical method, applied to rat ovary samples following subacute EDC exposure, revealed some new findings for toxicological evaluation. In particular, we showed that EDCs with the same described in vitro mechanisms of action have different effects on the gonadal steroid balance. These results highlight the need to develop an integrative evaluation with the simultaneous measurement of EDCs and numerous steroids for good risk assessment

    Human exposure assessment to a large set of polymer additives through the analysis of urine by solid phase extraction followed by ultra high performance liquid chromatography coupled to tandem mass spectrometry

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    International audiencePolymer items are extensively present in the human environment. Humans may be consequently exposed to some compounds, such as additives, incorporated in these items. The objective of this work is to assess the human exposure to the main additives such as those authorized in the packaging for pharmaceutical products. The urinary matrix was selected to optimally answer this challenge because it has already been proven that the exposure to chemicals can be revealed by the analysis of this biological matrix. A multi-residue analytical method for the trace analysis at ng/mL in human urine was developed, and consisted of an extraction of analytes from urine by solid phase extraction (SPE) and an analysis by ultra-high performance liquid chromatography coupled to a tandem mass spectrometer (UHPLC–MS/MS). Even if the quantification of these compounds was an analytical challenge because of (i) the presence of these substances in the analytical process, (ii) the diversity of their physicochemical properties, and (iii) the complexity of the matrix, the optimized method exhibited quantification limits lower than 25 ng/mL and recoveries between 51% and 120% for all compounds. The method was validated and applied to 52 human urines. To the best of our knowledge, this work presents the first study allowing the assessment of the occurrence of more than twenty polymer additives at ng/mL in human urine

    Determination of endocrine disruptors and endogenic androgens and estrogens in rat serum by high-performance liquid chromatography–tandem mass spectrometry

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    International audienceTo simultaneously measure some targeted endocrine disruptors and several forms of sex hormones in rat serum, an accurate analytical procedure was developed. First, a comparison between a polymeric-based solid-phase extraction (SPE) and a micro-extraction by packed sorbent was performed to choose the optimal method to extract and concentrate the analytes: bisphenol A, atrazine, vinclozolin metabolite, testosterone, androstenedione, estrone, estradiol, estrone-sulfate and glucuronide and estradiol-sulfate and glucuronide. The analyses were then performed by high-performance liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) with electrospray ionisation in positive and negative modes. The protocol based on SPE was validated using the ICH/2005 guidelines. The validation demonstrated good performance in terms of linearity (R2 > 0.99), recovery (71–90%) and repeatability (relative standard deviation: 1–18%). The method was sensitive with LOQ comprised between 0.1 and 0.4 ng/ml for androgens and between 0.098 and 10.2 ng/ml for estrogens. The results obtained on the serum of rats exposed to the targeted endocrine disruptors showed the suitability of this analytical strategy

    Multi-residue analysis of free and conjugated hormones and endocrine disruptors in rat testis by QuEChERS-based extraction and LC-MS/MS

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    International audienceEndocrine disrupting compounds (EDCs) are suspected to be responsible for many disorders of the human reproductive system. To establish a causality relationship between exposure to endocrine disruptors and disease, experiments on animals must be performed with improved or new analytical tools. Therefore, a simple, rapid, and effective multi-residue method was developed for the determination of four steroid hormones (i.e., testosterone, androstenedione, estrone, and estradiol), glucuronide and sulfate conjugates of estrone and estradiol and four endocrine disruptors in rat testis (i.e., bisphenol A, atrazine, and active metabolites of methoxychlor and vinclozolin). The sample preparation procedure was based on the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) approach. An analytical method was then developed to quantify these compounds at ultra-trace levels by liquid chromatography coupled to tandem mass spectrometry. The QuEChERS extraction was optimized with regard to the acetonitrile/water ratio used in the extraction step, the choice of the cleanup method and the acetonitrile/hexane ratio used in the cleanup step. The optimized extraction method exhibited recoveries between 89% and 108% for all tested compounds except the conjugates (31% to 58%). The detection limits of all compounds were below 20 ng g(-1) of wet weight of testis. The method was subsequently applied to determine the levels of hormones and EDCs in seven rat testis samples
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