Links between declining human male fertility (decreased sperm counts, increased incidence of both testicular cancer and genital abnormalities) and the increasing prevalence of endocrine disrupting chemicals (EDCs) in the environment have been reported. We aim to characterise the key developmental processes occurring during human fetal gonad development. Human fetal testis development was characterised by a transient increase in interstitial area proliferation between 13-19 weeks which was accompanied by an increase in steroidogenic acute regulatory protein (StAR) and steroidogenic enzymes. Androgen receptor was expressed by the peritubular myoid cells which had a high bcl-2:bax ratio, indicative of cell survival. Estrogen receptors ( and ) were localised to distinct cell populations. In the ovine gonad similar developmental processes occurred, and comparison with human ovarian development demonstrated interesting parallels. After optimisation, the explant culture system revealed that exposure to the insecticidal EDC dieldrin, at low (<1 ppb) doses reduced LH-stimulated testosterone output in the human fetal testis. This was accompanied by dose-specific changes to the testis proteome, alterations in bcl-2:bax ratios in favour of apoptosis and a down-regulation in StAR expression relative to the LH-treated controls. In conclusion, the processes of proliferation apoptosis, steroidogenesis and steroid action are crucial during fetal gonad development. We demonstrated that in utero exposure to dieldrin may cause reproductive dysfunction in adult life due to reduced steroidogenesis in the fetal gonad; mediated through a down-regulation in StAR expression and alterations in the regulation of gonadal apoptosis.

Many chemicals released into the environment are believed to disrupt normal endocrine functions in humans and animals. These endocrine disrupting chemicals (EDCs) affect reproductive health and development. A major group of EDCs that could be responsible for reproductive effects are those that mimic natural oestrogens, known as xeno-oestrogens. A number of in vivo and in vitro screening strategies are being developed to identify and classify xeno-oestrogens, in order to determine whether they pose a health risk to humans and animals. It is also important to be able to apply the assays to environmental samples for monitoring purposes. In South Africa information on the levels of EDCs in water is limited. While establishing the recombinant yeast screen bioassay (RCBA) using the yeast strain Sacchyromyces cerivisiae for oestrogenic activity, problems were experienced with contamination. Four South African laboratory water sources were assessed. From the results it was clear that the water used in the preparation of the medium for the assay was the source of oestrogenic contamination. Care should be taken to eliminate all possible sources of contamination in the test procedures to eliminate the reporting of false positive results. The fact that South African laboratory and surface waters tested positive for estrogenic activity has far reaching implications regarding reproductive and general health.

Endocrine disrupting chemicals (EDCs) are compounds in the environment that interfere with hormone systems in the body. I investigated if gestational exposure to a known class of EDCs, polychlorinated biphenyls (PCBs), resulted in life long alterations in neuroendocrine function. My overall hypothesis was that prenatal PCB exposure would cause molecular and cellular changes to the developing hypothalamus that would manifest across development through differences in hypothalamic gene expression, molecular epigenetic modifications, and corresponding effects on sexual development. To perform this work, I characterized changes in gene expression in two regions of the hypothalamus required for reproductive function throughout the life cycle and measured changes in somatic markers associated with reproductive physiology and development. This approach allowed me to relate specific neuroendocrine changes back to altered reproductive function. First, I present normative data showing gene and hormone changes throughout development in male and female rats to use as a basis of comparison for my further studies on EDCs. Second, I investigated how gestational exposure to PCBs on embryonic day 16 and 18 affected development of the hypothalamus through adulthood and caused corresponding changes in physiological functions. PCBs altered estrous cyclicity in females and delayed the timing of puberty in males. Developmental changes in gene expression were associated with sex, age and region of the hypothalamus. As a whole, the data suggested that gestational exposure to PCBs altered a network of hypothalamic genes and was associated with altered reproductive physiology. Finally, I extended my study farther along the life cycle to investigate if gestational exposure to PCBs altered the timing of reproductive aging in male and female rats. Few effects in males were observed. However, females exposed to PCBs had lower serum concentrations of LH on proestrus, and altered expression of numerous genes in the hypothalamus. These changes in gene expression were specific to the females’ cycle status and the results provided novel insight into the molecular mechanisms underlying reproductive aging. Taken together, my dissertation resulted in a comprehensive profile of both normal hypothalamic developmental changes, as well as providing insight into endocrine disruption of hypothalamic gene networks from birth through aging. / text

The endocrine disrupting chemicals (EDCs) are exogenous compounds that mimic natural hormones and disrupt endocrine functions in humans and animals. Accumulating evidence suggests that EDCs may have detrimental impact on human reproduction including infertility, distortion of sex ratios and menstrual problems. TCDD, one of the most toxic man-made chemicals, was found to affect embryo maturity, implantation and reproduction. Bisphenol A (BPA), another EDC commonly used nowadays in plastic products, exhibits weak estrogenic activity in human bodies. However, TCDD and BPA have distinct chemical structures, chemical properties and receptor binding, and their mechanistic actions on human body remain largely unknown. The present study is to delineate the effects of EDCs on embryo implantation and development under in vitro exposure. It is hypothesized that EDCs (TCDD and BPA) may modulate fertility of animals by affecting early pre-implantation embryo development and attachment onto uterus. The effect of EDCs on the expression of receptors (AhR, ERE, ERR,,and ERa) and downstream reporter genes (CYP1A1 and C3) were studied by real-time PCR and Western blotting. An in vitro spheroid (JEG-3)-endometrial cells (Ishikawa) co-culture assay was established to study the effect of EDCs on spheroid attachment. Since microRNA, Wnt-signaling and adhesion molecules play important roles in implantation process, the expression of selected miRNA, Wnt-signaling and adhesion molecules was studied after EDCs treatment. Specific activities of the EDCs receptors were confirmed by inhibitor treatment or siRNA knockdown studies. Furthermore, EDC-treated embryos were transferred to pseudo-pregnant surrogate mice to determine the effect of EDCs on implantation outcome on day 8. It was found that Ishikawa and JEG-3 cells expressed AhR, ERIIand ERRE. TCDD treatment induced CYP1A1 expression in both cell lines (P<0.05). TCDD at 10nM significantly suppressed (P<0.005) spheroid attachment (74% compared to control 97%). When both cell lines were treated with AhR antagonists DMF (10 aaa/ANF (1 /////with TCDD (10nM), the suppressive effect of TCDD on spheroid attachment in co-culture assay was nullified, suggesting that TCDD acts through AhR receptor. In BPA exposure, BPA (0.001 to 10 tt) induced the expressions of ER))and C3ain Ishikawa but reduced the expressions of EReeand C3ain JEG-3 cells. BPA (10 iiiisuppressed spheroids attachment (74% vs Control 94%, P<0.005); while co-treatment with ER antagonists (ICI 182,780), ERaaantagonistaaMPP), ERMMantagonist (PTHPP) or ERE///siRNA, the suppressive effect of BPA (10sM) on spheroid attachment was nullified, suggesting that BPA acts through ER receptors. Moreover, TCDD and BPA suppressed the expressions of B-catenin and E-cadherin for cell-cell adhesion. Activation of Wnt-signaling pathway by Wnt3a conditioned medium or LiCl, rescued the low spheroid attachment rate induced by EDCs. Both EDCs reduced embryo implantation rate in pseudo-pregnant mice, suggesting the adverse effect of EDCs on embryo implantation and/or endometrial receptivity. Taken together, TCDD and BPA affected the JEG-3 spheroid attachment onto the Ishikawa endometrial cells and mouse embryo implantation. These effects might be mediated through the action of receptors and Wnt/β-catenin signaling pathway. / published_or_final_version / Obstetrics and Gynaecology / Doctoral / Doctor of Philosophy

Thesis (Ph. D.)--Michigan State University. Dept. of Zoology-Environmental Toxicology, 2008. / Title from PDF t.p. (viewed on Mar. 30, 2009) Includes bibliographical references. Also issued in print.

Phthalates are endocrine-disrupting chemicals (EDCs) that are known testicular toxicants, used commonly as industrial plasticizers that are found in everyday items. Di-(2-ethylhexyl) phthalate (DEHP) is the most abundant phthalate in the environment, and its primary metabolite mono-(2-ethylhexyl) phthalate (MEHP) is ten-fold more potent. The purpose of this study is to examine the cellular and molecular effects of MEHP in the development of testicular cancer. Proliferation was measured for NT2 cells exposed to 10µM and 100µM MEHP at 24 and 48 hours and for cells under controlled conditions. Methylation-specific PCR (MSP) was used to determine the methylation status of the promoter region of key testicular genes post exposure to MEHP. MEHP caused a dose-dependent negative effect on proliferation and significantly altered methylation levels for key testicular genes following exposure to 10µM MEHP and 100µM, as compared to controls. This suggests that MEHP alters proliferation and methylation of testicular tumour cells in a time- and dose-dependent manner.

This critical overview document (COD) presents, discusses and brings together the selected portfolio of publications that the author believes make a significant contribution to the field of wastewater treatment, focusing on the removal of endocrine disrupting chemicals (EDCs) in wastewater treatment applications. The aim of the research within this COD was to investigate the fate, mechanisms and optimisation of EDCs removal in wastewater treatment applications. The key objectives were to: 1. Investigate and understand the mechanisms of removal of EDCs in wastewater and sludge treatment processes. 2. Evaluate novel methods for the removal of EDCs in water and wastewater treatment applications. 3. Establish the kinetic and thermodynamic properties of the removal processes to inform process modelling of full scale design of treatment processes.

Vinclozolin (VCZ), an antiandrogenic fungicide, is an endocrine disrupting chemical that is known to possess high affinity for the androgen receptor (AR) and modulate expression of critical androgen-dependant genes in the prostate. In this study, viability and expression of AR, NKX3.1 and CYP3A4 genes were measured in androgen-sensitive prostate cells LNCaP after exposure to VCZ and VCZ treated with S9 microsomes in a time and dose dependent manner. NKX3.1 is an androgen regulated gene that plays a vital role in prostate development. CYP3A4 is involved in xenobiotic metabolism. VCZ decreased the viability at high doses after 48 hours which was slightly mitigated by treatment with S9 metabolites. Expression of NKX3.1 and CYP3A4 was upregulated while an initial downregulation of AR was observed. NKX3.1 upregulation corroborates with possibility of antiandrogens to act as androgens in LNCaP. The results illustrate that VCZ can interfere with the expression of critical prostate genes.

Because of the structural resemblance to the female hormone, phytoestrogen is another important class of endocrine disruptor. In the present project, we evaluated the effects of phytoestrogens isoliquiritigenin (ILN), hesperetin (HES), genistein, (GEN) and naringenin (NAR) on estrogen metabolism and also their effects on MCF-7 tumor growth in ovariectomized nude mice. We found that these phytoestrogens had differential effect on MCF-7 xenografts. NAR and GEN had totally different responses in the tumor growth. In contrast, ILN and HES only deterred MCF-7 xenograft growth when CYP19 was overexpressed in the graft. / Breast cancer is one of the most prevalent female cancers in Hong Kong and western countries. Prolonged exposure to estrogen has been associated with increased risk of breast cancer. Many enzymes are responsible for estrogen metabolism, for instance, aromatase (CYP19) is responsible for biosynthesis; CYP1 family enzymes hydroxylate estrogen; COMT (catechol-O-methyltransferase) inactivates the hydroxyestrogen; and UDP-glucuronosyltransferase 1A1 (UGT1A1) eliminates the estrogen metabolites. In this project, we employed cell and animal models to address estrogen metabolism-related questions under the influence of endocrine disruptors. / TCDD is a prototype compound of a whole class of halogenated aromatic hydrocarbons termed dioxin-like contaminants, which are also known to be endocrine disruptors. Because of their persistence in the environment dioxins are one of the most concerned classes of carcinogens. Humans can be exposed to this pollutant through contaminated food, air, drinking water, etc. We found that pre-ovariectomy administration of TCDD could significantly reduce aromatase expression in the brain but increase the expression in the adipose tissue. Our results suggested that the timing of exposure to the toxicant could determine the estrogenicity of TCDD. / The present project indicated that endocrine disruptors can alter the metabolism of estrogen; however, the significance of this alteration may be specific to tissues' phenotype and the timing of exposure. / Ye Lan. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 169-192). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Orientador: Newton Luiz Dias Filho / Banca: Enes Furlani Junior / Banca: André Rodrigues dos Reis / Banca: Edemar Benedetti Filho / Banca: Gilberto José de Arruda / Resumo: Desruptoress endócrinos (D.E), como por exemplo, os pesticidas, representam uma classe emergente de contaminantes em sistemas aquáticos, que pode comprometer a vida da biota aquática e de seres humanos. Embora alguns estudos estejam sendo desenvolvidos no sentido de quantificação e verificação da toxicidade dos D.E presentes no ambiente, praticamente não há na literatura registros de estudos associados ao comportamento e disponibilidade destas substâncias em águas superficiais. Este trabalho buscou determinar a presença dos herbicidas 2,4-D(ácido 2,4-diclorofenoxiacético), Atrazina e Linuron e do inseticida Paration Metil, considerados D.E pela literatura internacional, nas águas do Rio Aporé e propor perspectivas de tratamento de águas de sistemas hídricos por meio de adsorventes sólidos de baixo custo. Este rio está localizado no cerrado brasileiro, o qual é marco divisor do Estado de Mato Grosso do Sul com o Estado de Goiás e recebe grande carga de resíduos de produção agrícola. Após a coleta de amostras de água em pontos estratégicos, foi feita extração pela técnica de Extração em Fase Sólida, em cartuchos de sílica C-18 e a detecção em Cromatografia Gasosa acoplada com detector de Espectrometria de Massas. Os materiais testados para a remoção dos pesticidas alvo deste trabalho foram obtidos a partir de: i) argila organicamente modificada com o surfactante N-dodecil-2-pirrolidona (Mo-DDP); ii) garrafas de PET pós uso (PET); III) biomassa de pinhão manso - J. curcas L. (TPMAN); iv) cinzas de casca de arroz (CCA); v) sílica gel organicamente modificada com 2-Amino-1,3,4- thiadiazol (SGT) e vi) carvão ativado a partir de casca de coco (CA). Os estudos de detecção e quantificação dos pesticidas nas águas do Rio Aporé demonstraram a presença dos pesticidas Malation e Dibutilftalato, os quais são considerados D.E por órgãos governamentais brasileiro,... / Abstract: Endocrine disrupters chemical (EDC), such as pesticides, represent an emerging class of contaminants in aquatic systems that can compromise the life of aquatic biota and human. Although some studies are being developed to quantify and verify the toxicity of EDC in the environment, there is almost no literature records related to the conduct studies and availability of these substances in surface waters. The aim of this study was to verity the presence of herbicide 2,4-D (diclorfenoxacetic acid), Atrazine and Linuron and insecticide Methyl Paration in Aporé River to propose perspectives of treatment in these waters by using low cost adsorbents. This river is located at the Brazilian savanna region, river that is located between Mato Grosso do Sul state and Goias state and receives a great amount of agricultural production waste. After collecting an amount of water at strategic points, has been done an extraction by the technical of Solid Phase Extraction, in cartridges of silica C-18, the detection in Gas Chromatography, attached with a detector Mass Spectrometry. The materials tested for the removal of pesticides, targeted in this study, were obtained from the: i) organically modified clays with surfactant N-dodecyl-2-pyrrolidone (Mo-DDP); ii) PET- Polyethylene terephthalate bottle after use (PET); III) biomass of J. curcas L. (TPMAN); iv) rice husk ash (RHA); v) silica gel organically modified with 2-Amino-1,3,4-thiadiazole (SGT) and vi) activated carbon from coconut shell (AC). Studies of detection and quantification of pesticides on the Aporé River's water demonstrate the presence of pesticides Malathion and Dibutyl phthalate(DBP), which are considered EDC by Brazilian, American and European government agencies. The adsorbents used had positive parameters to use for removal of these molecules, both in batch studies when fixed bed. The adsorption parameters tested showed that 60 to 120 min. ... / Doutor