Class Of Endocrine-disrupting Chemicals Research Articles

New perspectives on the bioremediation of endocrine disrupting compounds from wastewater using algae-, bacteria- and fungi-based technologies

Growing population and industrialization have resulted in a significant contamination of freshwater by a variety of micropollutants including endocrine disrupting chemicals (EDCs). Wastewater treatment plants cannot completely remove EDC yet, which then end up in wastewater effluents, and they are discharged directly into the environment. Rising concerns over the current EDC management strategies have created interest in sustainable and environmentally responsible wastewater treatment technologies. One promising option for remediation of EDC is to enhance treatment plants’ performance using microbial communities, microalgae or fungi. Here, the efficacy of these biological candidates is quantitatively reviewed, along with the operational conditions under which the highest degradation performance of selected classes of EDC, i.e., hormones, phenols, phthalates, pharmaceuticals, pesticides and formulation ingredients, is achieved. Using a formal meta-analysis, the main findings are highlighted: (1) the effect of Exposure time on biodegradation varies by EDC class, and this is influenced by Organism class (QM (df = 4) = 13.43, p = 0.0094); (2) the effect of the Organism class size (i.e., monoculture vs. multi-cultures) is influenced by EDC class (QM (df = 3) = 8.7470, p = 0.0329); (3) EDC complexity of contamination affects biodegradation (QM (df = 4) = 10.6652, p = 0.0306); (4) the effect of Organism class significantly varies by Delivery mechanism, and it is influenced by Carrier Material (QM (df = 5) = 14.3498, p = 0.0135); (5) biodegradation is affected by the unique features of EDC within the same EDC class, and (6) results are not impacted by the initial EDC concentration in the trials.

Perfluoroalkyl substances and bone health in young men: a pilot study.

Perfluoroalkyl substances (PFAS) are a class of endocrine-disrupting chemicals. Toxicological studies indicate that PFAS accumulate in bone tissue and could cause alterations in bone metabolism. The primary objective of this study was to examine the association between PFAS exposure and bone status in a cohort of young men resident in a well-defined area with high PFAS environmental pollution. Bone status was assessed in 117 subjects aged 18-21 by quantitative ultrasound (QUS) at the heel. Subjects underwent an accurate medical visit. Socio-demographic characteristics, lifestyle, and medical histories were collected. We also verified the interaction between PFAS and hydroxyapatite by computational modelling. The organic anion-transporting peptide (OATP), the putative transporter of PFAS, was evaluated by qPCR in bone biopsies from femoral heads discarded during arthroplasty in three male subjects. Exposed subjects showed significantly lower stiffness index, which resulted in lower t-score and higher prevalence of subjects at medium-high risk of fracture (23.6%) compared with controls (9.7%). Data from computational modelling suggested that PFOA exhibits a high affinity for hydroxyapatite, since the estimated change in free energy is in the order of that exhibited by bisphosphonates. Finally, we observed consistent expression of OATP1A2 gene in primary human osteoblasts. This is the first study reporting increased osteoporosis risk in young men exposed to PFAS and provide preliminary information on molecular mechanisms that could explain this observation, in agreement with previous studies on animal models and humans. However, these results must be interpreted with caution given the cross-sectional study design and the small number of cases.

Rapid, sensitive and simultaneous determination of 16 endocrine-disrupting chemicals (parabens, benzophenones, bisphenols, and triclocarban) in human urine based on microextraction by packed sorbent combined with liquid chromatography tandem mass spectrometry (MEPS-LC-MS/MS)

A high demand exists in human biomonitoring studies for reliable and straightforward methods that generate data faster and simultaneously. Thus, the present study combines microextraction by packed sorbent (MEPS) and liquid chromatography coupled to mass spectrometry (LC-MS/MS) for simultaneous extraction and determination of various classes of endocrine-disrupting chemicals (EDCs), including parabens, benzophenones, bisphenols, and the antimicrobial, triclocarban in human urine samples. Optimized MEPS conditions were: i) MEPS sorbent (C18), ii) pH of sample (3), iii) volume of sample (250 μL), iv) number of draws–eject cycles (5) and (vi) desorption solvent conditions (100 μL of CH3OH:H2O 80:20 v/v). The calibration curves were linear over the selected ranges for all studied compound, with correlation coefficients higher than 0.99. The variation coefficient for precision was lower than 20% at lower concentrations and lower than 15% at the higher concentrations studied. The accuracy ranged from 90% to 118%. The proposed strategy affords several advantages over currently published approaches, including simplicity of operation and reduction of sample and solvent volumes and time for matrix clean-up. Moreover, the analytical performance of each MEPS cartridge remained stable over the analysis of at least 70 samples (RSD < 10%). Thus, the current procedure may be an interesting high-throughput alternative for large routine human biomonitoring studies. Urinary geometric mean concentrations of EDCs obtained in this study were close than those previously reported for Brazilian children.

Phthalate Metabolites, Hydroxy-Polycyclic Aromatic Hydrocarbons, and Bisphenol Analogues in Bovine Urine Collected from China, India, and the United States.

Human exposure to endocrine-disrupting chemicals (EDCs) has aroused considerable public concern over the last three decades. Nevertheless, little is known with regard to the exposure of EDCs in farm animals. In this study, concentrations of 22 phthalate metabolites (PhMs), 15 hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs), and 8 bisphenols (BPs) were determined in 183 bovine urine samples collected from China, India, and the United States. The median concentrations of urinary PhMs, OH-PAHs, and BPs in bovines, collectively, were 66, 4.6, and 16 ng/mL, respectively. Mono-n-butyl phthalate (mBP; median, 14 ng/mL) and ∑4DEHP (four secondary metabolites of di(2-ethylhexyl) phthalate; 13 ng/mL) were the dominant PhMs; hydroxy-fluorene (OH-Fluo; 1.2 ng/mL) and -phenanthrene (OH-Phen; 1 ng/mL) were the dominant OH-PAHs; and 4,4'-di-hydroxydiphenylmethane (BPF; 10 ng/mL) and 2,2-bis(4-hydroxyphenyl) propane (BPA; 6.7 ng/mL) were the dominant BPs. Bovine urine samples from India and China contained the highest concentrations of PhMs and OH-PAHs, whereas those from India and the United States contained the highest concentrations of BPs. PhM and OH-PAH concentrations were significantly higher in the urine of bulls than those of cows; no such difference was found for BPs. Our findings establish baseline exposure information about three classes of EDCs in domestic farm animals.

Attention Worthy: Prenatal Phthalate Exposure and Subsequent ADHD Diagnosis.

Open in a separate window Exposure to phthalates, a class of endocrine-disrupting chemicals (EDCs) used in plastics manufacture, is ubiquitous.1 Some research suggests that phthalates may adversely affect neurodevelopment,2,3,4 potentially increasing the risk of attention deficit/hyperactivity disorder (ADHD).5,6 A study published in Environmental Health Perspectives found that prenatal exposure to certain phthalate metabolites was associated with increased odds of clinically confirmed ADHD in a group of 3-year-old children.7 Originally, phthalate research focused on reproductive end points, owing to the similarity between these chemicals and the steroidal hormones that control reproductive tract development and function. However, epidemiological studies have also reported associations between phthalate exposure and behaviors linked to ADHD, although the findings have been inconsistent.6,8,9,10,11,12 Open in a separate window More than 5% of children in the United States have ADHD, a disorder characterized by impaired focus and working memory. Improved diagnosis may partly, but not entirely, explain recent increases in prevalence of the disorder, which appears to have both genetic and environmental underpinnings.14 Image: © gali estrange/Shutterstock.

Analytical methods for urinary biomarkers of human exposure to phthalates

Phthalates (PAEs) are a class of endocrine-disrupting chemicals. In recent years, the harmful effects of PAEs on human health, in particular their toxicity toward the reproductive system and development, have received significant attention because of their increasing production and usage. PAEs are ubiquitous in the environment and food products, resulting in unavoidable and long-term exposure in humans. Therefore, exposure and risk assessments of PAEs in humans are necessary. Screening and quantification of phthalate metabolites in urine is an important method for evaluating PAEs exposure, and establishing accurate analytical methods for this purpose has become a high priority. Phthalate monoesters and secondary metabolites are the most commonly targeted biomarkers of exposure to short-and long-chain PAEs, respectively. The combination of off-line or on-line solid phase extraction (SPE) with high performance liquid chromatography-tandem mass spectrometry has become the preferred method for the determination of phthalate metabolites. This paper reviews the analytical methods available for the detection of urinary phthalate metabolites and discusses the advantages, limitations, and challenges presented by each method in practical applications.

Determination of 17 potential endocrine-disrupting chemicals in human saliva by dispersive liquid-liquid microextraction and liquid chromatography-tandem mass spectrometry

Endocrine-disrupting chemicals are a group of emerging contaminants that alters the function of the endocrine system, causing possible adverse health effects. In this study, a dispersive liquid-liquid microextraction method coupled with liquid chromatography-mass spectrometry for the simultaneous determination of 17 potential EDCs, bisphenols (A, S, P, AP, AF, Z), parabens (methyl-, ethyl-, propyl-, butyl-, benzyl-paraben), benzophenones (3, 1, 2, 8, 4-OH BP) and triclocarban, in human saliva samples was developed. Several parameters such as, type and volume of extraction and dispersive solvents, pH sample, ionic strength and, agitation, that affect extraction efficiency were investigated. Under the optimized conditions, the matrix-matched calibration curves of all analytes presented correlation coefficients higher than 0.99 (range level of 1–20 ng mL−1). The intra and inter-day coefficient of variation and relative standard deviation were lower than 20%, at 1 ng mL−1. The limits of detection and quantification ranged from 0.01 to 0.15 ng mL−1 and 0.05–0.40 ng mL−1, respectively. Finally, the proposed method was applied in the simultaneous determination of several endocrine-disrupting chemicals classes in 10 human saliva samples In conclusion, the proposed method is an attractive alternative for application in large-scale human biomonitoring studies.

Urinary concentrations of parabens mixture and pregnancy glucose levels among women from a fertility clinic

BackgroundA number of endocrine disrupting chemicals (EDC) have been associated with gestational diabetes (GDM) risk factors. However, no human study has investigated the association between pregnancy exposure to parabens, a class of EDCs, and pregnancy glucose levels, a risk factor for GDM. Furthermore, little is known about this association in subfertile women—a group at high risk of GDM. MethodsA total of 241 women from the Environment and Reproductive Health Study had data available on 1st and/or 2nd trimester urinary methylparaben, propylparaben, and butylparaben concentrations, and blood glucose levels after the glucose loading test (GLT), a non-fasting 50 g glucose loading test taken at late 2nd trimester. Trimester-specific associations between specific gravity adjusted methylparaben, butylparaben, and propylparaben with adjusted mean of pregnancy glucose levels were evaluated in linear regression models, using quartiles of each paraben's distribution, and as a paraben mixture, using mutual adjustment and Bayesian kernel machine regression (BKMR), a recently proposed method for investigating chemical mixtures that flexibly models the joint effect of chemicals. ResultsInvestigating parabens one at the time did not provide any significant results. When investigating parabens as a chemical mixture with both multiple regression and BKMR, we observed positive associations of butylparaben (e.g comparing the 4th and 1st quartiles) with glucose levels, for both the 1st trimester (adjusted difference=12.5 mg/dL; 95% CI: 0.9, 24.2) and 2nd trimester (adjusted difference=11.2 mg/dL; 95% CI: 0.2, 22.3), and a negative association between 1st trimester propylparaben and glucose (adjusted difference=−22.3 mg/dL; 95% CI: −43.2, −1.4). ConclusionsWe found 1st trimester butylparaben and propylparaben urinary concentrations to be associated with glucose levels in a pregnancy cohort of women at high risk of GDM, even after adjusting for potential confounders. Because exposure to parabens is widespread, these findings may suggest further investigating the effects of this chemical class on pregnancy health.

Effects of the Endocrine-Disrupting Chemicals, Vinclozolin and Polychlorinated Biphenyls, on Physiological and Sociosexual Phenotypes in F2 Generation Sprague-Dawley Rats.

Background:Exposure to endocrine-disrupting chemicals (EDCs) during gestation influences development of the F1 generation offspring and can result in disease and dysfunction in adulthood. Limited evidence suggests consequences on the F2 generation, exposed as germ cells within the F1 fetus. These F2s provide a unique window into the programming effects of EDCs.Objective:This study assessed intergenerational effects of EDC exposure on adult physiology and behavior in Sprague-Dawley rats.Methods:Pregnant rats were exposed to either a polychlorinated biphenyl (PCB) mixture, Aroclor 1,221 (A1221), the fungicide vinclozolin (VIN), or the vehicle (VEH) (6% dimethylsulfoxide in sesame oil) alone. A1221 is weakly estrogenic, while VIN is antiandrogenic, enabling us to compare different classes of EDCs. The F1 male and female offspring were bred to generate the paternal- and maternal-lineage F2 generation. This F2 generation was assessed for physiological outcomes, ultrasonic vocalizations (USVs), and sexual behavior in adulthood.Results:Each EDC caused phenotypic effects in a sex- and lineage-dependent manner. The most robustly affected group was the paternal-lineage males. F2 VIN paternal male descendants had increased body weight throughout the lifespan, lower concentrations of circulating estradiol, and lower adrenal and testicular indices. Both VIN and A1221 paternal-lineage males also exhibited the greatest number of changes in the characteristics of USVs in response to an opposite-sex animal and changes in sexual behaviors in a mating test.Conclusion:Exposure of rats to EDCs at the germ cell stage led to differences in the physiological and behavioral phenotype later in life, especially in males. This finding has implications for multigenerational physiological and reproductive health in wildlife and humans. https://doi.org/10.1289/EHP3550

Maternal Exposure to Perfluorooctane Sulfonate (PFOS) Is Associated with Maternal Hyperglycaemia and Adverse Neonatal and Childhood Outcomes

Perfluorooctane sulfonate (PFOS) belongs to a class of endocrine-disrupting chemicals, perfluoroalkyl chemicals (PFCs), implicated in adiposity. Although supposedly phased out since 2002, its use remains widespread in Asia. We aim to examine the relationship between exposure to PFOS and maternal hyperglycaemia and metabolic outcomes in the offspring. We measured blood PFOS and other PFCs in archived samples taken at 24-32weeks gestation from mothers in the Hong Kong centre of the Hyperglycaemia and Adverse Pregnancy Outcome (HAPO) study between 2002-2004. All mothers underwent 75g OGTT and GDM was diagnosed according to the IADPSG/WHO 2013 criteria. Pregnancy outcomes, neonatal anthropometrics and childhood outcomes at 7 years were documented. PFCs were measured using high performance LC-MS-MS. We completed analysis of PFCs in 1,601 maternal samples, a subset of 99 cord blood samples, and 970 offspring at 7 years follow-up. There is strong correlation among PFOS and other PFCs in cord blood (ρ=0.51-0.74, p&amp;lt;0.001), as well as correlation with maternal levels (ρ=0.60, p&amp;lt;0.001). Ratio of cord blood to maternal PFOS was 0.60. Using regression analysis with adjustment for maternal age, BMI, and offspring gender, maternal PFOS showed association with maternal 1 hour glucose, 2 hour glucose, HbA1c, AUC during OGTT and GDM, though only the association with HbA1c remained significant using log-transformed PFOS (beta 0.0746 ± 0.0132, p=1.7x10-8). Log-transformed maternal PFOS was associated with higher birthweight, lower birth length, higher ponderal index and lower neonatal sum of skin fold thickness (beta -0.337 ± 0.085, p=7.1x 10-5), after adjustment for all covariates. Maternal PFOS during pregnancy was associated with lower height in offspring at age 7, but not offspring glycaemic parameters. Exposure to PFOS may be an important contributing factor to the epidemic of hyperglycaemia in pregnancy and childhood metabolic disorders in Asia. Disclosure R.C.W. Ma: Research Support; Self; AstraZeneca, Bayer AG, Merck Sharp &amp; Dohme Corp., Pfizer Inc.. Advisory Panel; Self; Boehringer Ingelheim GmbH, Nippon Boehringer Ingelheim Co. Ltd.. C.H.T. Tam: None. G. Cheung: None. W. Lowe: None. B.E. Metzger: None. W.H. Tam: None. C.K. Wong: None.

Endocrine-disrupting chemicals and the regulation of energy balance.

Energy balance involves the adjustment of food intake, energy expenditure and body fat reserves through homeostatic pathways. These pathways include a multitude of biochemical reactions, as well as hormonal cues. Dysfunction of this homeostatic control system results in common metabolism-related pathologies, which include obesity and type 2 diabetes mellitus. Metabolism-disrupting chemicals (MDCs) are a particular class of endocrine-disrupting chemicals that affect energy homeostasis. MDCs affect multiple endocrine mechanisms and thus different cell types that are implicated in metabolic control. MDCs affect gene expression and the biosynthesis of key enzymes, hormones and adipokines that are essential for controlling energy homeostasis. This multifaceted spectrum of actions precludes compensatory responses and favours metabolic disorders. Herein, we review the main mechanisms used by MDCs to alter energy balance. This work should help to identify new MDCs, as well as novel targets of their action.

Anxiety-like behaviors in adulthood are altered in male but not female rats exposed to low dosages of polychlorinated biphenyls in utero

Exposure to polychlorinated biphenyls (PCBs), a class of endocrine-disrupting chemicals, can result in altered reproductive behavior in adulthood, especially when exposure occurs during critical periods of brain sexual differentiation in the fetus. Whether PCBs alter other sexually dimorphic behaviors such as those involved in anxiety is poorly understood. To address this, pregnant rat dams were injected twice, on gestational days 16 and 18, with the weakly estrogenic PCB mixture Aroclor 1221 (A1221) at one of two low dosages (0.5mg/kg or 1.0mg/kg, hereafter 1.0 and 0.5), estradiol benzoate (EB; 50μg/kg) as a positive estrogenic control, or the vehicle (3% DMSO in sesame oil). We also conducted a comprehensive assessment of developmental milestones of the F1 male and female offspring. There were no effects of treatment on sex ratio at birth and age at eye opening. Puberty, assessed by vaginal opening in females and preputial separation in males, was not affected in females but was advanced in males treated with A1221 (1.0). Males and females treated with A1221 (both dosages) were heavier in early adulthood relative to controls. The earliest manifestation of this effect developed in males prior to puberty and in females slightly later, during puberty. Anxiety-like behaviors were tested using the light:dark box and elevated plus maze tests in adulthood. In females, anxiety behaviors were unaffected by treatment. Males treated with A1221 (1.0) showed reduced indices of anxiety and increased activity in the light:dark box but not the elevated plus maze. EB failed to replicate the phenotype produced by A1221 for any of the developmental and behavioral endpoints. Collectively, these results indicate that PCBs increase body weight in both sexes, but their effects on anxiety-like behaviors are specific to males. Furthermore, differences between the results of A1221 and EB suggest that the PCBs are likely acting through mechanisms distinct from their estrogenic activity.

Two-hit exposure to polychlorinated biphenyls at gestational and juvenile life stages: 1. Sexually dimorphic effects on social and anxiety-like behaviors

Endocrine disrupting chemicals (EDCs) are widespread environmental contaminants that affect many neuroendocrine functions. The brain is particularly vulnerable to EDCs during critical periods of gestational development when gonadal hormones exert organizational effects on sexually dimorphic behaviors later in life. Peripubertal development is also a time of continued neural sensitivity to organizing effects of hormones, yet little is known about EDC actions at these times. We sought to determine effects of prenatal or juvenile exposures to a class of EDCs, polychlorinated biphenyls (PCBs) at human-relevant dosages on development, physiology, and social and anxiety-related behaviors later in life, and the consequences of a second juvenile “hit” following prenatal treatment. We exposed male and female Sprague–Dawley rats to PCBs (Aroclor 1221, 1mg/kg/day, ip injection) and/or vehicle during prenatal development (embryonic days 16, 18, 20), juvenile development (postnatal days 24, 26, 28), or both. These exposures had differential effects on behaviors in sex and age-dependent ways; while prenatal exposure had more effects than juvenile, juvenile exposure often modified or unmasked the effects of the first hit. Additionally, females exhibited altered social and anxiety behavior in adolescence, while males displayed small but significant changes in sociosexual preferences in adulthood. Thus, the brain continues to be sensitive to organizing effects of EDCs through juvenile development. As humans are exposed to EDCs throughout multiple periods in their life, these findings have implications for our understanding of EDC effects on physiology and behavior.

Determination of 13 endocrine disrupting chemicals in environmental solid samples using microwave-assisted solvent extraction and continuous solid-phase extraction followed by gas chromatography-mass spectrometry.

Soil can contain large numbers of endocrine disrupting chemicals (EDCs). The varied physicochemical properties of EDCs constitute a great challenge to their determination in this type of environmental matrix. In this work, an analytical method was developed for the simultaneous determination of various classes of EDCs, including parabens, alkylphenols, phenylphenols, bisphenol A, and triclosan, in soils, sediments, and sewage sludge. The method uses microwave-assisted extraction (MAE) in combination with continuous solid-phase extraction for determination by gas chromatography-mass spectrometry. A systematic comparison of the MAE results with those of ultrasound-assisted and Soxhlet extraction showed MAE to provide the highest extraction efficiency (close to 100%) in the shortest extraction time (3 min). The proposed method provides a linear response over the range 2.0 - 5000 ng kg(-1) and features limits of detection from 0.5 to 4.5 ng kg(-1) depending on the properties of the EDC. The method was successfully applied to the determination of target compounds in agricultural soils, pond and river sediments, and sewage sludge. The sewage sludge samples were found to contain all target compounds except benzylparaben at concentration levels from 36 to 164 ng kg(-1). By contrast, the other types of samples contained fewer EDCs and at lower concentrations (5.6 - 84 ng kg(-1)).

Monitoring of phthalates in foodstuffs using gas purge microsyringe extraction coupled with GC–MS

Phthalate esters (PAEs) are commonly used as nonreactive plasticisers in vinyl plastics to increase the flexibility of plastic polymers. Numerous studies have indicated that the PAEs as a class of endocrine-disrupting chemicals. In addition, the studies have also shown that a major source of human exposure to phthalates is the diet. To date, the largest problem in PAEs analysis is the high blank value because PAEs are widely used in various applications and products. To overcome this shortcoming, gas purge microsyringe extraction (GP-MSE) was applied, which established a new and low-blank-value analytical method for PAE analysis to analyse PAEs in foodstuffs. In this study, GP-MSE was used as a clean-up method, and the overall recoveries ranged from 85.7 to 102.6%, and the RSD was less than 10%. More importantly, this method can overcome the problem of the high blank value in PAE analysis. This method was applied for measuring PAEs in 78 foodstuffs. The results showed that a wide variety of PAE concentrations were found in the different groups, and the content of PAEs (varies from 658 to 1610ngg−1 fresh weight) is greatest in seafood. The concentrations were in the following order: DEHP>DBP>DEP≈DMP>BBP≈DNOP. Finally, the daily intake of PAEs was estimated for adults based on the levels of PAEs in foodstuffs. The total EDIdiet values of 3.2 and 12.9μgkg−1 bw d−1 were calculated for DEHP based on the mean and highest concentrations in foodstuffs, respectively.

Infertile women who conceived using assisted reproductive technology (ART) have lower urinary phthalate concentrations than infertile women who conceived spontaneously

Phthalates, a class of endocrine-disrupting chemicals, are ubiquitous in the environment and have been linked to many adverse health outcomes. We examined the association between phthalate exposure and time > 1 year to conceive, with or without use of fertility treatments for pregnancy.

Interaction of 17β-estradiol and ketoconazole on endocrine function in goldfish (Carassius auratus)

An understanding of the effects of toxic mixtures of endocrine disrupting chemicals (EDCs) on aquatic organisms is challenging as these organisms are exposed to multiple classes of contaminants in their natural habitat. The aim of the present study was to evaluate the interactions of two classes of EDCs, 17β-estradiol (E2) and ketoconazole (KTC), on endocrine function in male goldfish (Carassius auratus), including vitellogenesis, metabolic capability and serum steroid synthesis. Changes in vitellogenin (VTG) concentration, liver 7-ethoxyresorufin-O-deethylase (EROD) activity and circulating serum E2 level were examined. The expression of related genes was also determined using quantitative real-time polymerase chain reaction. Exposure to E2 caused a significant increase in VTG concentrations which corresponded with the gene expression of VTG and estrogen receptor (ER) in males, which were further elevated after combined exposure to E2 and KTC, indicative of a synergetic relationship. Exposure to E2 also resulted in a distinct increase in serum steroid biosynthesis and associated cytochrome P450 (CYP) aromatase expression after 10 days. However, these changes were inhibited by the presence of KTC, which acted as a steroidogenic inhibitor in fish. Moreover, KTC significantly decreased liver EROD activity and increased the related gene expression of CYP1A. However, these KTC-mediated metabolic reactions in goldfish were up-regulated following exposure to KTC in combination with E2. These findings reveal complex interactions on endocrine functions in male goldfish when exposed to multiple contaminations and may provide a better understanding of the effects of toxic mixtures.

97 THE REGULATION OF UTERINE CONTRACTION BY ENDOCRINE-DISRUPTING CHEMICALS IN RATS

Environmental oestrogens, class of endocrine-disrupting chemicals, are defined as compounds that bind the oestrogen receptors and elicit or modulate an ER-mediated response. Examples of suspected environmental oestrogenic chemicals include plastic components such as bisphenol A (BPA) and some components of detergents and their biodegradation products, 4-octylphenol (OP). The uterus frequently contracts throughout the entire menstrual cycle, and these contractions have been termed endometrial waves or contractile waves. The balanced contractile waves play an important role in regulating oestrus or menstrual cycles, implantation, maintaining pregnancy, and parturition. The uterine contraction has been known to be regulated by contraction-associated proteins such as oxytocin, oxytocin receptor (OTR), connexin 43, prostaglandin F2 alpha receptor (FP), and 15-hydroxy prostaglandin dehydrogenase (PDGH). Endogenous steroid hormones including oestrogen and progesterone have been shown to regulate contraction-associated proteins and, thereby, modify uterine contraction. Forty female immature rats were divided into 8 groups, each group composed of 5 rats. They were injected subcutaneously daily for 3 days with BPA and OP at doses of 20, 100, and 500 mg kg–1 of BW per day; 17β-estradiol (E2, 40 µg kg–1 per day) was a positive control. After 24 h of the final treatment, the rats were euthanized and the uteri were collected for further experiments. Total RNA and protein were extracted from uteri. The mRNA expressions for CaBP-9k, oxytocin, OTR, FP, and PDGH were determined by real-time PCR with specific primers, and the protein levels were examined by Western blot assay. The data were analyzed using a one-way ANOVA. The P-values &lt;0.05 were considered statistically significant. The treatment of oestrogenic compounds significantly regulated the contraction-associated proteins. First, the mRNA levels of CaBP-9k that is a biomarker for evaluating oestrogenicity in the rats were significantly induced by positive control, E2. Chemicals OP and BPA at doses of 100 and 500 mg kg–1 also induced the gene expression of CaBP-9k. Oxytocin and OTR were highly augmented by OP (40 fold) and BPA (6-fold) at a dose of 500 mg kg–1 compared with control, whereas PDGH was moderately upregulated by the chemicals. Interestingly, FP was decreased by E2 and high doses of OP and BPA. These results showed that exposure of immature rats to BPA and OP regulated expression of oxytocin, OTR, PDGH, and FP genes in the rat uterus. Taken together, uterine contraction and physiological conformational change of the uterus were affected by exposure to oestrogenic endocrine-disrupting chemicals. Because balanced contractile activity of the uterus maintains regular menstrual cycles, pregnancy, and labor, alteration of the contractility raised by oestrogenic compounds may cause severe adverse effects on the female reproductive system.

Prevalent glucocorticoid and androgen activity in US water sources.

Contamination of the environment with endocrine disrupting chemicals (EDCs) is a major health concern. The presence of estrogenic compounds in water and their deleterious effect are well documented. However, detection and monitoring of other classes of EDCs is limited. Here we utilize a high-throughput live cell assay based on sub-cellular relocalization of GFP-tagged glucocorticoid and androgen receptors (GFP-GR and GFP-AR), in combination with gene transcription analysis, to screen for glucocorticoid and androgen activity in water samples. We report previously unrecognized glucocorticoid activity in 27%, and androgen activity in 35% of tested water sources from 14 states in the US. Steroids of both classes impact body development, metabolism, and interfere with reproductive, endocrine, and immune systems. This prevalent contamination could negatively affect wildlife and human populations.

Enhanced screening efficiency for endocrine-disrupting chemicals in milk and powdered milk using UPLC/QTOF-MS by the introduction of dansyl chloride derivatisation

This study developed and validated a sensitive analytical method for simultaneous screening of four classes of endocrine-disrupting chemicals (i.e. progestogens, androgens, oestrogens and phenols) in milk and powdered milk using ultra-performance liquid chromatography (UPLC) coupled with electrospray ionisation quadrupole time-of-flight mass spectrometry (QTOF-MS). Dansylation of oestrogens and phenols enhanced the ionisation efficiency and shifted the ionisation mode from negative to positive, which allowed for the simultaneous analysis of four EDCs in one chromatographic run. An efficient sample pre-treatment minimised the matrix effects. The mass errors for the precursor and product ions for 26 target compounds varied between −2.8 and 2.3 mDa; and the limits of detection (signal-to-noise ratio = 3) for milk and powdered milk were less than 0.04 µg l−1 and 0.10 µg kg−1, respectively. The proposed method was successfully used to analyse multiple types of real samples, including normal temperature whole milk, infant formula and whole powdered milk. In 11 samples, two target compounds, progesterone and androstenedione, were detected. The progesterone concentrations ranged from 8.1 to 12.7 µg l−1 in milk, and from 1.2 to 32.0 µg kg−1 in infant formulas and whole powdered milks. The androstenedione concentrations varied from 0.39 to 0.79 µg l−1 in milks, and from 0.29 to 1.2 µg kg−1 in infant formulas and whole powdered milks. Two post-target compounds, one isomer of oestriol and 5α-dihydroprogesterone, were tentatively identified by post-target analysis in two of 11 real samples.