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vom Saal FS, Antoniou M, Belcher SM, Bergman A, Bhandari RK, Birnbaum LS, Cohen A, Collins TJ, Demeneix B, Fine AM, Flaws JA, Gayrard V, Goodson WH, Gore AC, Heindel JJ, Hunt PA, Iguchi T, Kassotis CD, Kortenkamp A, Mesnage R, Muncke J, Myers JP, Nadal A, Newbold RR, Padmanabhan V, Palanza P, Palma Z, Parmigiani S, Patrick L, Prins GS, Rosenfeld CS, Skakkebaek NE, Sonnenschein C, Soto AM, Swan SH, Taylor JA, Toutain PL, von Hippel FA, Welshons WV, Zalko D, Zoeller RT. The Conflict between Regulatory Agencies over the 20,000-Fold Lowering of the Tolerable Daily Intake (TDI) for Bisphenol A (BPA) by the European Food Safety Authority (EFSA). Environ Health Perspect 2024; 132:45001. [PMID: 38592230 PMCID: PMC11003459 DOI: 10.1289/ehp13812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 03/05/2024] [Accepted: 03/05/2024] [Indexed: 04/10/2024]
Abstract
BACKGROUND The European Food Safety Authority (EFSA) recommended lowering their estimated tolerable daily intake (TDI) for bisphenol A (BPA) 20,000-fold to 0.2 ng / kg body weight ( BW ) / day . BPA is an extensively studied high production volume endocrine disrupting chemical (EDC) associated with a vast array of diseases. Prior risk assessments of BPA by EFSA as well as the US Food and Drug Administration (FDA) have relied on industry-funded studies conducted under good laboratory practice protocols (GLP) requiring guideline end points and detailed record keeping, while also claiming to examine (but rejecting) thousands of published findings by academic scientists. Guideline protocols initially formalized in the mid-twentieth century are still used by many regulatory agencies. EFSA used a 21st century approach in its reassessment of BPA and conducted a transparent, but time-limited, systematic review that included both guideline and academic research. The German Federal Institute for Risk Assessment (BfR) opposed EFSA's revision of the TDI for BPA. OBJECTIVES We identify the flaws in the assumptions that the German BfR, as well as the FDA, have used to justify maintaining the TDI for BPA at levels above what a vast amount of academic research shows to cause harm. We argue that regulatory agencies need to incorporate 21st century science into chemical hazard identifications using the CLARITY-BPA (Consortium Linking Academic and Regulatory Insights on BPA Toxicity) nonguideline academic studies in a collaborative government-academic program model. DISCUSSION We strongly endorse EFSA's revised TDI for BPA and support the European Commission's (EC) apparent acceptance of this updated BPA risk assessment. We discuss challenges to current chemical risk assessment assumptions about EDCs that need to be addressed by regulatory agencies to, in our opinion, become truly protective of public health. Addressing these challenges will hopefully result in BPA, and eventually other structurally similar bisphenols (called regrettable substitutions) for which there are known adverse effects, being eliminated from all food-related and many other uses in the EU and elsewhere. https://doi.org/10.1289/EHP13812.
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Affiliation(s)
- Frederick S. vom Saal
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, USA
| | - Michael Antoniou
- Department of Medical and Molecular Genetics, King’s College London School of Medicine, London, UK
| | - Scott M. Belcher
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Ake Bergman
- Department of Environmental Science (ACES), Stockholm University, Stockholm, Sweden
| | - Ramji K. Bhandari
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, USA
| | - Linda S. Birnbaum
- Scientist Emeritus and Former Director, National Toxicology Program (NTP), National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
- Scholar in Residence, Duke University, Durham, North Carolina, USA
| | - Aly Cohen
- Integrative Rheumatology Associates, Princeton, New Jersey, USA
| | - Terrence J. Collins
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Barbara Demeneix
- Comparative Physiology Laboratory, Natural History Museum, Paris, France
| | - Anne Marie Fine
- Environmental Medicine Education International, Mancos, Colorado, USA
| | - Jodi A. Flaws
- Department of Comparative Biosciences, University of Illinois Urbana—Champaign, Urbana-Champaign, Illinois, USA
| | - Veronique Gayrard
- ToxAlim (Research Centre in Food Toxicology), University of Toulouse, Toulouse, France
| | - William H. Goodson
- California Pacific Medical Center Research Institute, San Francisco, California, USA
| | - Andrea C. Gore
- Division of Pharmacology and Toxicology, University of Texas at Austin, Austin, Texas, USA
| | - Jerrold J. Heindel
- Healthy Environment and Endocrine Disruptor Strategies, Raleigh, North Carolina, USA
| | - Patricia A. Hunt
- School of Molecular Biosciences, Center for Reproductive Biology, Washington State University, Pullman, Washington, USA
| | - Taisen Iguchi
- Graduate School of Nanobioscience, Yokohama City University, Yokohama, Japan
| | - Christopher D. Kassotis
- Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan, USA
- Department of Pharmacology, Wayne State University, Detroit, Michigan, USA
| | - Andreas Kortenkamp
- Centre for Pollution Research and Policy, Brunel University London, Uxbridge, UK
| | - Robin Mesnage
- Department of Medical and Molecular Genetics, King’s College London School of Medicine, London, UK
| | - Jane Muncke
- Food Packaging Forum Foundation, Zurich, Switzerland
| | | | - Angel Nadal
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE) and CIBERDEM, Miguel Hernandez University of Elche, Elche, Alicante, Spain
| | - Retha R. Newbold
- Scientist Emeritus, NTP, NIEHS, Research Triangle Park, North Carolina, USA
| | - Vasantha Padmanabhan
- Department of Pediatrics, Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Paola Palanza
- Unit of Neuroscience, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | | | - Stefano Parmigiani
- Unit of Evolutionary and Functional Biology, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Lyn Patrick
- Environmental Medicine Education International, Mancos, Colorado, USA
| | - Gail S. Prins
- Department of Urology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Cheryl S. Rosenfeld
- Biomedical Sciences, Thompson Center for Autism and Neurobehavioral Disorders, University of Missouri—Columbia, Columbia, Missouri, USA
- MU Institute of Data Science and Informatics, University of Missouri—Columbia, Columbia, Missouri, USA
| | - Niels E. Skakkebaek
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Carlos Sonnenschein
- Department of Immunology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Ana M. Soto
- Department of Immunology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Shanna H. Swan
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Julia A. Taylor
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, USA
| | - Pierre-Louis Toutain
- Royal Veterinary College, University of London, London, UK
- NTHERES, INRAE, ENVT, Université de Toulouse, Toulouse, France
| | - Frank A. von Hippel
- Department of Community, Environment & Policy, University of Arizona, Tucson, Arizona, USA
| | - Wade V. Welshons
- Department of Biomedical Sciences, University of Missouri—Columbia, Columbia, Missouri, USA
| | - Daniel Zalko
- ToxAlim (Research Centre in Food Toxicology), University of Toulouse, Toulouse, France
| | - R. Thomas Zoeller
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, USA
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Howdeshell KL, Beverly BEJ, Blain RB, Goldstone AE, Hartman PA, Lemeris CR, Newbold RR, Rooney AA, Bucher JR. Evaluating endocrine disrupting chemicals: A perspective on the novel assessments in CLARITY-BPA. Birth Defects Res 2023; 115:1345-1397. [PMID: 37646438 DOI: 10.1002/bdr2.2238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/17/2023] [Accepted: 07/31/2023] [Indexed: 09/01/2023]
Abstract
BACKGROUND The Consortium Linking Academic and Regulatory Insights on Bisphenol A Toxicity (CLARITY-BPA) was a collaborative research effort to better link academic research with governmental guideline studies. This review explores the secondary goal of CLARITY-BPA: to identify endpoints or technologies from CLARITY-BPA and prior/concurrent literature from these laboratories that may enhance the capacity of rodent toxicity studies to detect endocrine disrupting chemicals (EDCs). METHODS A systematic literature search was conducted with search terms for BPA and the CLARITY-BPA participants. Relevant studies employed a laboratory rodent model and reported results on 1 of the 10 organs/organ systems evaluated in CLARITY-BPA (brain and behavior, cardiac, immune, mammary gland, ovary, penile function, prostate gland and urethra, testis and epididymis, thyroid hormone and metabolism, and uterus). Study design and findings were summarized, and a risk-of-bias assessment was conducted. RESULTS Several endpoints and methods were identified as potentially helpful to detect effects of EDCs. For example, molecular and quantitative morphological approaches were sensitive in detecting alterations in early postnatal development of the brain, ovary, and mammary glands. Hormone challenge studies mimicking human aging reported increased susceptibility of the prostate to disease following developmental BPA exposure. Statistical analyses for nonmonotonic dose responses, and computational approaches assessing multiple treatment-related outcomes concurrently in linked hormone-sensitive organ systems, reported effects at low BPA doses. CONCLUSIONS This review provided an opportunity to evaluate the unique insights provided by nontraditional assessments in CLARITY-BPA to identify technologies and endpoints to enhance detection of EDCs in future studies.
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Affiliation(s)
- Kembra L Howdeshell
- Division of Translational Toxicology, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
| | - Brandiese E J Beverly
- Division of Translational Toxicology, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
| | | | | | | | | | - Retha R Newbold
- Division of Translational Toxicology, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
- NIEHS, retired, Research Triangle Park, North Carolina, United States
| | - Andrew A Rooney
- Division of Translational Toxicology, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
| | - John R Bucher
- Division of Translational Toxicology, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
- NIEHS, retired, Research Triangle Park, North Carolina, United States
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Abstract
Abstract
Studies have shown that developmental exposure to genistein alters murine reproductive differentiation, resulting in abnormal ovarian development (multioocyte follicles) and uterine neoplasia later in life. Further, reproductive function was altered. Prolonged estrous cyclicity was observed following neonatal genistein treatment (0.550 mg/kg) on Days 15 with doseand age-related increase in severity. Fertility, determined at 2, 4, and 6 months, showed decreased numbers of genistein-treated females (0.5 or 5 mg/kg) delivering live pups and reduced numbers of pups. At 6 months, 60% of 0.5 mg/kg and 40% of 5 mg/kg groups delivered live pups compared to 100% of controls. At 2 months, half the mice treated with 25 mg/kg of genistein and none treated with 50 mg/kg delivered live pups, although half of the latter group showed signs of pregnancy with few small implantation sites. Ovarian function was disrupted in the low genistein-dosed mice with increased numbers of corpora lutea (CLs) compared to controls and increased ovulated oocytes following exogenous gonadotropins treatment. In contrast, mice treated with high genistein doses had decreased numbers of CLs; ovulation could be restored with exogenous gonadotropins. Thus, neonatal treatment with genistein at environmentally relevant doses caused adverse consequences on ovarian development and reproductive function.
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Affiliation(s)
- Wendy N Jefferson
- National Institute of Environmental Health Sciences, National Institute of Health, Department of Health and Human Services, Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, Research Triangle Park, NC 27709
| | - Elizabeth Padilla-Banks
- National Institute of Environmental Health Sciences, National Institute of Health, Department of Health and Human Services, Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, Research Triangle Park, NC 27709
| | - Retha R Newbold
- National Institute of Environmental Health Sciences, National Institute of Health, Department of Health and Human Services, Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, Research Triangle Park, NC 27709
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Walker VR, Boyles AL, Pelch KE, Holmgren SD, Shapiro AJ, Blystone CR, Devito MJ, Newbold RR, Blain R, Hartman P, Thayer KA, Rooney AA. Human and animal evidence of potential transgenerational inheritance of health effects: An evidence map and state-of-the-science evaluation. Environ Int 2018; 115:48-69. [PMID: 29549716 DOI: 10.1016/j.envint.2017.12.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 12/18/2017] [Accepted: 12/20/2017] [Indexed: 05/21/2023]
Abstract
BACKGROUND An increasing number of reports suggest early life exposures result in adverse effects in offspring who were never directly exposed; this phenomenon is termed "transgenerational inheritance." Given concern for public health implications for potential effects of exposures transmitted to subsequent generations, it is critical to determine how widespread and robust this phenomenon is and to identify the range of exposures and possible outcomes. OBJECTIVES This scoping report examines the evidence for transgenerational inheritance associated with exposure to a wide range of stressors in humans and animals to identify areas of consistency, uncertainty, data gaps, and to evaluate general risk of bias issues for the transgenerational study design. METHODS A protocol was developed to collect and categorize the literature into a systematic evidence map for transgenerational inheritance by health effects, exposures, and evidence streams following the Office of Health Assessment and Translation (OHAT) approach for conducting literature-based health assessments. RESULTS A PubMed search yielded 63,758 unique records from which 257 relevant studies were identified and categorized into a systematic evidence map by evidence streams (46 human and 211 animal), broad health effect categories, and exposures. Data extracted from the individual studies are available in the Health Assessment Workspace Collaborative (HAWC) program. There are relatively few bodies of evidence where multiple studies evaluated the same exposure and the same or similar outcomes. Studies evaluated for risk of bias generally had multiple issues in design or conduct. CONCLUSIONS The evidence mapping illustrated that risk of bias, few studies, and heterogeneity in exposures and endpoints examined present serious limitations to available bodies of evidence for assessing transgenerational effects. Targeted research is suggested to addressed inconsistencies and risk of bias issues identified, and thereby establish more robust bodies of evidence to critically assess transgenerational effects - particularly by adding data on exposure-outcome pairs where there is some evidence (i.e., reproductive, metabolic, and neurological effects).
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Affiliation(s)
- Vickie R Walker
- Office of Health Assessment and Translation (OHAT), Division of National Toxicology Program (NTP), National Institute of Environmental Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC, USA.
| | - Abee L Boyles
- Office of Health Assessment and Translation (OHAT), Division of National Toxicology Program (NTP), National Institute of Environmental Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC, USA
| | - Katherine E Pelch
- Office of Health Assessment and Translation (OHAT), Division of National Toxicology Program (NTP), National Institute of Environmental Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC, USA
| | | | - Andrew J Shapiro
- Program Operations Branch, DNTP, NIEHS, NIH, DHHS, Research Triangle Park, NC, USA
| | - Chad R Blystone
- Toxicology Branch, DNTP, NIEHS, NIH, DHHS, Research Triangle Park, NC, USA
| | - Michael J Devito
- NTP Laboratory, DNTP, NIEHS, NIH, DHHS, Research Triangle Park, NC, USA
| | - Retha R Newbold
- Researcher Emeritus, DNTP, NIEHS, NIH, DHHS, Research Triangle Park, NC, USA
| | | | | | - Kristina A Thayer
- Office of Health Assessment and Translation (OHAT), Division of National Toxicology Program (NTP), National Institute of Environmental Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC, USA
| | - Andrew A Rooney
- Office of Health Assessment and Translation (OHAT), Division of National Toxicology Program (NTP), National Institute of Environmental Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC, USA
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Vandenberg LN, Gerona RR, Kannan K, Taylor JA, van Breemen RB, Dickenson CA, Liao C, Yuan Y, Newbold RR, Padmanabhan V, Vom Saal FS, Woodruff TJ. Erratum to: A round robin approach to the analysis of bisphenol a (BPA) in human blood samples. Environ Health 2016; 15:43. [PMID: 26956378 PMCID: PMC4782580 DOI: 10.1186/s12940-016-0126-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 03/01/2016] [Indexed: 06/05/2023]
Affiliation(s)
- Laura N Vandenberg
- Division of Environmental Health Sciences, University of Massachusetts -Amherst, School of Public Health, Amherst, MA, USA
| | - Roy R Gerona
- Department of Laboratory Medicine, University of California - San Francisco, San Francisco, CA, USA
| | - Kurunthachalam Kannan
- Wadsworth Center, New York State Department of Health, and State University of New York at Albany, Albany, NY, USA
| | - Julia A Taylor
- Division of Biological Sciences, University of Missouri, Columbia, MO, USA
| | | | - Carrie A Dickenson
- Program on Reproductive Health and the Environment, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California - San Francisco, San Francisco, CA, USA
| | - Chunyang Liao
- Wadsworth Center, NY State Department of Public Health, Albany, NY, USA
| | - Yang Yuan
- College of Pharmacy, University of Illinois, Chicago, IL, USA
| | - Retha R Newbold
- National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Vasantha Padmanabhan
- Department of Pediatrics and Reproductive Sciences Program, University of Michigan, Ann Arbor, MI, USA
| | | | - Tracey J Woodruff
- Program on Reproductive Health and the Environment, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California - San Francisco, San Francisco, CA, USA.
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Heindel JJ, Newbold RR, Williams CJ, Iguchi T, Tyler CR. Lou Guillette--in memorandum. Mol Reprod Dev 2015; 82:Fmi-v. [PMID: 26457800 DOI: 10.1002/mrd.22587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jerrold J Heindel
- Heindel National Institute of Environmental Health Sciences, Division of Extramural Research and Training
| | - Retha R Newbold
- Emeritus, National Institute of Environmental Health Sciences, Division of the National Toxicology Program
| | - Carmen J Williams
- National Institute of Environmental Health Sciences, Division of Intramural Research
| | - Taisen Iguchi
- Professor of Integrative Bioscience, National Institutes of Natural Sciences, National Institute for Basic Biology
| | - Charles R Tyler
- College of Life and Environmental Sciences, University of Exeter
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Vandenberg LN, Ehrlich S, Belcher SM, Ben-Jonathan N, Dolinoy DC, Hugo ER, Hunt PA, Newbold RR, Rubin BS, Saili KS, Soto AM, Wang HS, vom Saal FS. Low dose effects of bisphenol A. ACTA ACUST UNITED AC 2014. [DOI: 10.4161/endo.26490] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Vandenberg LN, Gerona RR, Kannan K, Taylor JA, van Breemen RB, Dickenson CA, Liao C, Yuan Y, Newbold RR, Padmanabhan V, vom Saal FS, Woodruff TJ. A round robin approach to the analysis of bisphenol A (BPA) in human blood samples. Environ Health 2014; 13:25. [PMID: 24690217 PMCID: PMC4066311 DOI: 10.1186/1476-069x-13-25] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 02/10/2014] [Indexed: 05/06/2023]
Abstract
BACKGROUND Human exposure to bisphenol A (BPA) is ubiquitous, yet there are concerns about whether BPA can be measured in human blood. This Round Robin was designed to address this concern through three goals: 1) to identify collection materials, reagents and detection apparatuses that do not contribute BPA to serum; 2) to identify sensitive and precise methods to accurately measure unconjugated BPA (uBPA) and BPA-glucuronide (BPA-G), a metabolite, in serum; and 3) to evaluate whether inadvertent hydrolysis of BPA-G occurs during sample handling and processing. METHODS Four laboratories participated in this Round Robin. Laboratories screened materials to identify BPA contamination in collection and analysis materials. Serum was spiked with concentrations of uBPA and/or BPA-G ranging from 0.09-19.5 (uBPA) and 0.5-32 (BPA-G) ng/mL. Additional samples were preserved unspiked as 'environmental' samples. Blinded samples were provided to laboratories that used LC/MSMS to simultaneously quantify uBPA and BPA-G. To determine whether inadvertent hydrolysis of BPA metabolites occurred, samples spiked with only BPA-G were analyzed for the presence of uBPA. Finally, three laboratories compared direct and indirect methods of quantifying BPA-G. RESULTS We identified collection materials and reagents that did not introduce BPA contamination. In the blinded spiked sample analysis, all laboratories were able to distinguish low from high values of uBPA and BPA-G, for the whole spiked sample range and for those samples spiked with the three lowest concentrations (0.5-3.1 ng/ml). By completion of the Round Robin, three laboratories had verified methods for the analysis of uBPA and two verified for the analysis of BPA-G (verification determined by: 4 of 5 samples within 20% of spiked concentrations). In the analysis of BPA-G only spiked samples, all laboratories reported BPA-G was the majority of BPA detected (92.2 - 100%). Finally, laboratories were more likely to be verified using direct methods than indirect ones using enzymatic hydrolysis. CONCLUSIONS Sensitive and accurate methods for the direct quantification of uBPA and BPA-G were developed in multiple laboratories and can be used for the analysis of human serum samples. BPA contamination can be controlled during sample collection and inadvertent hydrolysis of BPA conjugates can be avoided during sample handling.
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Affiliation(s)
- Laura N Vandenberg
- Division of Environmental Health Sciences, University of Massachusetts – Amherst, School of Public Health, Amherst, MA, USA
| | - Roy R Gerona
- Department of Laboratory Medicine, University of California – San Francisco, San Francisco, CA, USA
| | - Kurunthachalam Kannan
- Wadsworth Center, New York State Department of Health, and State University of New York at Albany, Albany, NY, USA
| | - Julia A Taylor
- Division of Biological Sciences, University of Missouri, Columbia, MO, USA
| | | | - Carrie A Dickenson
- Program on Reproductive Health and the Environment, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California – San Francisco, San Francisco, CA, USA
| | - Chunyang Liao
- Wadsworth Center, NY State Department of Public Health, Albany, NY, USA
| | - Yang Yuan
- College of Pharmacy, University of Illinois, Chicago, IL, USA
| | - Retha R Newbold
- National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Vasantha Padmanabhan
- Department of Pediatrics and Reproductive Sciences Program, University of Michigan, Ann Arbor, MI, USA
| | | | - Tracey J Woodruff
- Program on Reproductive Health and the Environment, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California – San Francisco, San Francisco, CA, USA
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Jefferson WN, Chevalier DM, Phelps JY, Cantor AM, Padilla-Banks E, Newbold RR, Archer TK, Kinyamu HK, Williams CJ. Persistently altered epigenetic marks in the mouse uterus after neonatal estrogen exposure. Mol Endocrinol 2013; 27:1666-77. [PMID: 24002655 DOI: 10.1210/me.2013-1211] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Neonatal exposure to diethylstilbestrol (DES) causes permanent alterations in female reproductive tract gene expression, infertility, and uterine cancer in mice. To determine whether epigenetic mechanisms could explain these phenotypes, we first tested whether DES altered uterine expression of chromatin-modifying proteins. DES treatment significantly reduced expression of methylcytosine dioxygenase TET oncogene family, member 1 (TET1) on postnatal day 5; this decrease was correlated with a subtle decrease in DNA 5-hydroxymethylcytosine in adults. There were also significant reductions in histone methyltransferase enhancer of zeste homolog 2 (EZH2), histone lysine acetyltransferase 2A (KAT2A), and histone deacetylases HDAC1, HDAC2, and HDAC3. Uterine chromatin immunoprecipitation was used to analyze the locus-specific association of modified histones with 2 genes, lactoferrin (Ltf) and sine oculis homeobox 1 (Six1), which are permanently upregulated in adults after neonatal DES treatment. Three histone modifications associated with active transcription, histone H3 lysine 9 acetylation (H3K9ac), H3 lysine 4 trimethylation (H3K4me3), and H4 lysine 5 acetylation (H4K5ac) were enriched at specific Ltf promoter regions after DES treatment, but this enrichment was not maintained in adults. H3K9ac, H4K5ac, and H3K4me3 were enriched at Six1 exon 1 immediately after neonatal DES treatment. As adults, DES-treated mice had greater differences in H4K5ac and H3K4me3 occupancy at Six1 exon 1 and new differences in these histone marks at an upstream region. These findings indicate that neonatal DES exposure temporarily alters expression of multiple chromatin-modifying proteins and persistently alters epigenetic marks in the adult uterus at the Six1 locus, suggesting a mechanism for developmental exposures leading to altered reproductive function and increased cancer risk.
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Affiliation(s)
- Wendy N Jefferson
- National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, PO Box 12233, MD E4-05, Research Triangle Park, North Carolina 27709.
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Davis VL, Newbold RR, Couse JF, Rea SL, Gallagher KM, Hamilton KJ, Goulding EH, Jefferson W, Eddy EM, Bullock BC, Korach KS. Expression of a dominant negative estrogen receptor alpha variant in transgenic mice accelerates uterine cancer induced by the potent estrogen diethylstilbestrol. Reprod Toxicol 2012; 34:512-21. [PMID: 22989549 PMCID: PMC4164054 DOI: 10.1016/j.reprotox.2012.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 08/02/2012] [Accepted: 08/24/2012] [Indexed: 12/21/2022]
Abstract
ERΔ3 transgenic mice expressing a dominant negative estrogen receptor α (ERα) variant lacking the second zinc finger in the DNA binding domain were developed to examine its potential to inhibit estrogen action in vivo. To investigate if ERΔ3 expression influences uterine carcinogenesis, ERΔ3 transgenic mice were exposed to diethylstilbestrol (DES) on post-natal days 1-5. Neonatal DES treatment induced uterine adenocarcinomas in 81% of 8-month-old ERΔ3 mice compared to 49% of wild-type females (p<0.016). ERΔ3 did not inhibit the expression of the estrogen-responsive progesterone receptor and lactoferrin genes in the presence of ERα or modify their expression in ERα knockout (αERKO) mice. Higher circulating 17β-estradiol levels and non-classical signaling by ERΔ3 may be related to the earlier incidence of uterine cancer. These findings indicate that expression of this ERα variant can influence determining events in uterine cancer development and its natural occurrence in the human uterus would unlikely be protective.
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Affiliation(s)
- Vicki L Davis
- Receptor Biology Group, Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, United States.
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Sargis RM, Howard SG, Newbold RR, Heindel JJ. THE DIABETES EPIDEMIC: Environmental Chemical Exposure in Etiology and Treatment. San Franc Med 2012; 85:18-20. [PMID: 24771962 PMCID: PMC3996836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Affiliation(s)
- Robert M Sargis
- Kovler Diabetes Center, Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Chicago
| | - Sarah G Howard
- Collaborative on Health and the Environment in Bolinas, California
| | - Retha R Newbold
- National Institute of Environmental Health Sciences, National Institutes of Health, in Research Triangle Park, North Carolina
| | - Jerrold J Heindel
- National Institute of Environmental Health Sciences, National Institutes of Health, in Research Triangle Park, North Carolina
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Newbold RR. Developmental exposure to endocrine-disrupting chemicals programs for reproductive tract alterations and obesity later in life. Am J Clin Nutr 2011; 94:1939S-1942S. [PMID: 22089436 PMCID: PMC3364077 DOI: 10.3945/ajcn.110.001057] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Many chemicals in the environment, especially those with estrogenic activity, are able to disrupt the programming of endocrine signaling pathways established during development; these chemicals are referred to as endocrine-disrupting chemicals. Altered programming can result in numerous adverse consequences in estrogen-target tissues, some of which may not be apparent until later in life. For example, a wide variety of structural, functional, and cellular effects have been identified in reproductive tract tissues. In addition to well-documented reproductive changes, obesity and diabetes have joined the list of adverse effects that have been associated with developmental exposure to environmental estrogens and other endocrine-disrupting chemicals. Obesity is a significant public health problem reaching epidemic proportions worldwide. Experimental animal studies document an association of developmental exposure to environmental estrogens and obesity. For example, a murine model of perinatal exposure to diethylstilbestrol has proven useful in studying mechanisms involved in abnormal programming of differentiating estrogen-target tissues, including reproductive tract tissues and adipocytes. Other environmental estrogens, including the environmental contaminant bisphenol A, have also been linked to reproductive problems and obesity later in life. Epidemiology studies support similar findings in humans, as do studies of cells in culture. Together, these findings suggest new targets for abnormal programming by estrogenic chemicals and provide evidence supporting the scientific concept termed the developmental origins of adult disease. Furthermore, the association of environmental estrogens with obesity and diabetes expands the focus on these diseases from intervention or treatment to include prevention or avoidance of chemical modifiers, especially during critical windows of development.
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Affiliation(s)
- Retha R Newbold
- Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA.
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Dixon D, Reed CE, Moore AB, Gibbs-Flournoy EA, Hines EP, Wallace EA, Stanko JP, Lu Y, Jefferson WN, Newbold RR, Fenton SE. Histopathologic changes in the uterus, cervix and vagina of immature CD-1 mice exposed to low doses of perfluorooctanoic acid (PFOA) in a uterotrophic assay. Reprod Toxicol 2011; 33:506-512. [PMID: 22146484 DOI: 10.1016/j.reprotox.2011.10.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 09/29/2011] [Accepted: 10/24/2011] [Indexed: 01/09/2023]
Abstract
The estrogenic and antiestrogenic potential of perfluorooctanoic acid (PFOA) was assessed using an immature mouse uterotrophic assay and by histologic evaluation of the uterus, cervix and vagina following treatment. Female offspring of CD-1 dams were weaned at 18days old and assigned to groups of equal weight, and received 0, 0.01, 0.1, or 1mg PFOA/kg BW/d by gavage with or without 17-β estradiol (E(2), 500μg/kg/d) from PND 18-20 (n=8/treatment/block). At 24h after the third dose (PND 21), uteri were removed and weighed. Absolute and relative uterine weights were significantly increased in the 0.01mg/kg PFOA only group. Characteristic estrogenic changes were present in all E(2)-treated mice; however, they were minimally visible in the 0.01 PFOA only mice. These data suggest that at a low dose PFOA produces minimal histopathologic changes in the reproductive tract of immature female mice, and does not antagonize the histopathologic effects of E(2).
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Affiliation(s)
- Darlene Dixon
- National Toxicology Program (NTP) Laboratories Branch, Division of the NTP, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA.
| | - Casey E Reed
- National Toxicology Program (NTP) Laboratories Branch, Division of the NTP, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Alicia B Moore
- National Toxicology Program (NTP) Laboratories Branch, Division of the NTP, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | | | - Erin P Hines
- Environmental Media Assessment Group, National Center for Environmental Assessment (NCEA), Office of Research and Development (ORD), U.S. EPA, Research Triangle Park, NC 27711, USA
| | - Elizabeth A Wallace
- National Toxicology Program (NTP) Laboratories Branch, Division of the NTP, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Jason P Stanko
- National Toxicology Program (NTP) Laboratories Branch, Division of the NTP, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Yi Lu
- Social & Scientific Systems, Inc., Durham, NC 27703, USA
| | - Wendy N Jefferson
- Laboratory of Reproductive and Developmental Toxicology, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Retha R Newbold
- NTP (retired), National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Suzanne E Fenton
- National Toxicology Program (NTP) Laboratories Branch, Division of the NTP, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA.
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Abstract
Puberty is an important transition that enables reproduction of mammalian species. Precocious puberty, specifically early thelarche (the appearance of breast "buds"), in girls of multiple ethnic backgrounds is a major health problem in the United States and other countries. The cause for a continued decrease in the age of breast development in girls is unknown, but environmental factors likely play a major role. Laboratory and epidemiological studies have identified several individual environmental factors that affect breast development, but further progress is needed. Current research needs include increased attention to and recording of prenatal and neonatal environmental exposures, testing of marketed chemicals for effects on the mammary gland, and understanding of the mammary gland-specific mechanisms that are altered by chemicals. Such research is required to halt the increasing trend toward puberty at earlier ages.
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Affiliation(s)
- Suzanne E Fenton
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, U.S. Department of Health and Human Services, Research Triangle Park, North Carolina 27709, USA.
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Newbold RR. Developmental Effects of Environmental Estrogens on Subsequent Fertility and Ovarian Function. Biol Reprod 2010. [DOI: 10.1093/biolreprod/83.s1.208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Doerge DR, Twaddle NC, Churchwell MI, Newbold RR, Delclos KB. Corrigendum to “Lactational transfer of the soy isoflavone, genistein, in Sprague–Dawley rats consuming dietary genistein” [Reprod Toxicol 21 (2006) 307–312]. Reprod Toxicol 2010. [DOI: 10.1016/j.reprotox.2010.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
Environmental chemicals with hormone-like activity can disrupt programming of endocrine signaling pathways during development and result in adverse effects, some of which may not be apparent until much later in life. Recent reports link exposure to environmental endocrine disrupting chemicals during development with adverse health consequences, including obesity and diabetes. These particular diseases are quickly becoming significant public health problems and are fast reaching epidemic proportions worldwide. This review summarizes data from experimental animals and humans which support an association of endocrine disrupting chemicals, such as diethylstilbestrol, bisphenol A, phytoestrogens, phthalates, and organotins, with the development of obesity. Potential mechanisms are summarized and future research needs are discussed.
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Affiliation(s)
- Retha R Newbold
- Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, and National Toxicology Program, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, North Carolina 27713, USA.
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Williams CJ, Jefferson WN, Padilla-Banks E, Goulding EH, Newbold RR. Long-Term Impact of Neonatal Genistein Exposure on Adult Oviductal Function in the Mouse.Carmen J. Williams, M.D., Ph.D. Biol Reprod 2009. [DOI: 10.1093/biolreprod/81.s1.59] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Adewale HB, Jefferson WN, Newbold RR, Patisaul HB. Neonatal bisphenol-a exposure alters rat reproductive development and ovarian morphology without impairing activation of gonadotropin-releasing hormone neurons. Biol Reprod 2009; 81:690-9. [PMID: 19535786 DOI: 10.1095/biolreprod.109.078261] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Developmental exposure to endocrine-disrupting compounds is hypothesized to adversely affect female reproductive physiology by interfering with the organization of the hypothalamic-pituitary-gonadal axis. Here, we compared the effects of neonatal exposure to two environmentally relevant doses of the plastics component bisphenol-A (BPA; 50 microg/kg and 50 mg/kg) with the ESR1 (formerly known as ERalpha)-selective agonist 4,4',4''-(4-propyl-[(1)H]pyrazole-1,3,5-triyl)trisphenol (PPT; 1 mg/kg) on the development of the female rat hypothalamus and ovary. An oil vehicle and estradiol benzoate (EB; 25 microg) were used as negative and positive controls. Exposure to EB, PPT, or the low dose of BPA advanced pubertal onset. A total of 67% of females exposed to the high BPA dose were acyclic by 15 wk after vaginal opening compared with 14% of those exposed to the low BPA dose, all of the EB- and PPT-treated females, and none of the control animals. Ovaries from the EB-treated females were undersized and showed no evidence of folliculogenesis, whereas ovaries from the PPT-treated females were characterized by large antral-like follicles, which did not appear to support ovulation. Severity of deficits within the BPA-treated groups increased with dose and included large antral-like follicles and lower numbers of corpora lutea. Sexual receptivity, examined after ovariectomy and hormone replacement, was normal in all groups except those neonatally exposed to EB. FOS induction in hypothalamic gonadotropic (GnRH) neurons after hormone priming was impaired in the EB- and PPT-treated groups but neither of the BPA-treated groups. Our data suggest that BPA disrupts ovarian development but not the ability of GnRH neurons to respond to steroid-positive feedback.
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Affiliation(s)
- Heather B Adewale
- Department of Biology, North Carolina State University, Raleigh, North Carolina, USA
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Newbold RR, Jefferson WN, Padilla-Banks E. Prenatal exposure to bisphenol a at environmentally relevant doses adversely affects the murine female reproductive tract later in life. Environ Health Perspect 2009; 117:879-85. [PMID: 19590677 PMCID: PMC2702400 DOI: 10.1289/ehp.0800045] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Accepted: 01/15/2009] [Indexed: 05/08/2023]
Abstract
BACKGROUND Exposure to endocrine-disrupting chemicals during critical developmental periods causes adverse consequences later in life; an example is prenatal exposure to the pharmaceutical diethylstilbestrol (DES). Bisphenol A (BPA), an environmental estrogen used in the synthesis of plastics, is of concern because its chemical structure resembles that of DES, and it is a "high-volume production" chemical with widespread human exposure. OBJECTIVES In this study we investigated whether prenatal BPA causes long-term adverse effects in female reproductive tissues in an experimental animal model previously shown useful in studying effects of prenatal DES. METHODS Timed pregnant CD-1 mice were treated on days 9-16 of gestation with BPA (0.1, 1, 10, 100, or 1,000 mug/kg/day). After delivery, pups were held for 18 months; reproductive tissues were then evaluated. RESULTS Ovarian cysts were significantly increased in the 1-mug/kg BPA group; ovarian cyst-adenomas were seen in the other three BPA-treated groups but not in corn-oil controls. We observed increased progressive proliferative lesions of the oviduct after BPA treatment, similar to those described in response to DES. Further, although not statistically different from the controls, prominent mesonephric (Wolffian) remnants and squamous metaplasia of the uterus, as well as vaginal adenosis, were present in BPA-treated mice, similar to lesions reported following DES treatment. More severe pathologies observed in some BPA-treated animals included atypical hyperplasia and stromal polyps of the uterus; sarcoma of the uterine cervix; and mammary adenocarcinoma. We did not observe these lesions in controls. CONCLUSIONS These data suggest that BPA causes long-term adverse reproductive and carcinogenic effects if exposure occurs during critical periods of differentiation.
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Affiliation(s)
- Retha R Newbold
- Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709, USA.
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Abstract
Many chemicals in the environment, in particular those with estrogenic activity, can disrupt the programming of endocrine signaling pathways that are established during development and result in adverse consequences that may not be apparent until much later in life. Most recently, obesity and diabetes join the growing list of adverse consequences that have been associated with developmental exposure to environmental estrogens during critical stages of differentiation. These diseases are quickly becoming significant public health issues and are fast reaching epidemic proportions worldwide. In this review, we summarize the literature from experimental animal studies documenting an association of environmental estrogens and the development of obesity, and further describe an animal model of exposure to diethylstilbestrol (DES) that has proven useful in studying mechanisms involved in abnormal programming of various differentiating estrogen-target tissues. Other examples of environmental estrogens including the phytoestrogen genistein and the environmental contaminant Bisphenol A are also discussed. Together, these data suggest new targets (i.e., adipocyte differentiation and molecular mechanisms involved in weight homeostasis) for abnormal programming by estrogenic chemicals, and provide evidence that support the scientific hypothesis termed "the developmental origins of adult disease". The proposal of an association of environmental estrogens with obesity and diabetes expands the focus on the diseases from intervention/treatment to include prevention/avoidance of chemical modifiers especially during critical windows of development.
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Affiliation(s)
- Retha R Newbold
- Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC 27709, United States.
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Ferguson SA, Delclos KB, Newbold RR, Flynn KM. Few effects of multi-generational dietary exposure to genistein or nonylphenol on sodium solution intake in male and female Sprague–Dawley rats. Neurotoxicol Teratol 2009; 31:143-8. [PMID: 19452615 DOI: 10.1016/j.ntt.2009.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Latendresse JR, Bucci TJ, Olson G, Mellick P, Weis CC, Thorn B, Newbold RR, Delclos KB. Genistein and ethinyl estradiol dietary exposure in multigenerational and chronic studies induce similar proliferative lesions in mammary gland of male Sprague-Dawley rats. Reprod Toxicol 2009; 28:342-53. [PMID: 19383540 DOI: 10.1016/j.reprotox.2009.04.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 04/06/2009] [Accepted: 04/11/2009] [Indexed: 10/20/2022]
Abstract
Genistein and ethinyl estradiol (EE(2)) were examined in multigenerational reproductive and 2-yr chronic toxicity studies with different exposure durations across generations F(0) through F(4). Sprague-Dawley rats were exposed to genistein (0, 5, 100, or 500 ppm) or EE(2) (0, 2, 10, or 50 ppb). Effects in the male mammary gland are described here. In the multigeneration studies, mammary hyperplasia was induced by both compounds; the chronic studies had a lower incidence, without proportionate neoplasia. Sexual dimorphism (predominant tubuloalveolar growth in females and lobuloalveolar in males) was retained without feminization in high dose genistein or EE(2). In the continuously exposed generations, mammary hyperplasia was sustained but not amplified, appeared morphologically similar across all generations, and was not carried over into unexposed offspring of previously exposed generations. The hyperplasia in male rats was similar whether induced by genistein or EE(2). Results substantiate and extend previous reports that mammary gland hyperplasia in the male rat is one of the most sensitive markers of estrogenic endocrine disruption.
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Delclos KB, Weis CC, Bucci TJ, Olson G, Mellick P, Sadovova N, Latendresse JR, Thorn B, Newbold RR. Overlapping but distinct effects of genistein and ethinyl estradiol (EE(2)) in female Sprague-Dawley rats in multigenerational reproductive and chronic toxicity studies. Reprod Toxicol 2009; 27:117-32. [PMID: 19159674 PMCID: PMC2706590 DOI: 10.1016/j.reprotox.2008.12.005] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Revised: 12/05/2008] [Accepted: 12/19/2008] [Indexed: 01/28/2023]
Abstract
Genistein and ethinyl estradiol (EE(2)) were examined in multigenerational reproductive and chronic toxicity studies that had different treatment intervals among generations. Sprague-Dawley rats received genistein (0, 5, 100, or 500 ppm) or EE(2) (0, 2, 10, or 50 ppb) in a low phytoestrogen diet. Nonneoplastic effects in females are summarized here. Genistein at 500 ppm and EE(2) at 50 ppb produced similar effects in continuously exposed rats, including decreased body weights, accelerated vaginal opening, and altered estrous cycles in young animals. At the high dose, anogenital distance was subtly affected by both compounds, and a reduction in litter size was evident in genistein-treated animals. Genistein at 500 ppm induced an early onset of aberrant cycles relative to controls in the chronic studies. EE(2) significantly increased the incidence of uterine lesions (atypical focal hyperplasia and squamous metaplasia). These compound-specific effects appeared to be enhanced in the offspring of prior exposed generations.
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Affiliation(s)
- K Barry Delclos
- National Center for Toxicological Research, Jefferson, AR 72079, USA.
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Jefferson WN, Padilla-Banks E, Goulding EH, Lao SPC, Newbold RR, Williams CJ. Neonatal exposure to genistein disrupts ability of female mouse reproductive tract to support preimplantation embryo development and implantation. Biol Reprod 2008; 80:425-31. [PMID: 19005167 DOI: 10.1095/biolreprod.108.073171] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Female mice treated neonatally with the phytoestrogen genistein (50 mg/kg/day) have multioocyte follicles, lack regular estrous cyclicity, and are infertile even after superovulation. To determine the cause of their infertility, we examined oocyte developmental competence and timing of embryo loss. Eggs obtained by superovulation of genistein-treated or control females were equally capable of being fertilized in vitro and cultured to the blastocyst stage. However, if eggs were fertilized in vivo, retrieved at the pronucleus stage, and cultured, there was a significant reduction in the percentage of embryos from genistein-treated females reaching the blastocyst stage. When these blastocysts were transferred to pseudopregnant recipients, the number of live pups produced was similar to that in controls. Preimplantation embryo development in vivo was examined by flushing embryos from the oviduct and/or uterus. Similar numbers of one-cell and two-cell embryos were obtained from genistein-treated and control females. However, significantly fewer embryos (<50%) were obtained from genistein-treated females on postcoital Days 3 and 4. To determine if neonatal genistein treatment altered the ability of the uterus to support implantation, blastocysts from control donors were transferred to control and genistein-treated pseudopregnant recipients. These experiments demonstrated that genistein-treated females are not capable of supporting normal implantation of control embryos. Taken together, these results suggest that oocytes from mice treated neonatally with genistein are developmentally competent; however, the oviductal environment and the uterus have abnormalities that contribute to the observed reproductive failure.
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Affiliation(s)
- Wendy N Jefferson
- Reproductive Medicine Group, Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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Jefferson WN, Voelker CR, Newbold RR. Increased Sensitivity of Western Blots Using Various Secondary Antibody Detection Methods. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15376519309047234] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Jefferson WN, Shigeta H, Newbold RR. Enhanced Chemiluminescent Detection of Fluorescein-Labeled Nucleic Acids Compared to32P Labeling Methods: Lactoferrin as a Marker. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15376519509045903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Jefferson WN, Teng C, Newbold RR. Methodologies for Isolating Estrogen-Responsive Proteins as Markers of Environmental Toxicants. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15376519609066119] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
Environmental chemicals with hormone-like activity can disrupt the programming of endocrine signalling pathways that are established during perinatal life and result in adverse consequences that may not be apparent until much later in life. Increasing evidence implicates developmental exposure to environmental hormone mimics with a growing list of adverse health consequences in both males and females. Most recently, obesity has been proposed to be yet another adverse health effect of exposure to endocrine disrupting chemicals (EDCs) during critical stages of development. Obesity is quickly becoming a significant human health crisis because it is reaching epidemic proportions worldwide, and is associated with chronic illnesses such as diabetes and cardiovascular disease. In this review, we summarize the literature reporting an association of EDCs and the development of obesity, and further describe an animal model of exposure to diethylstilbestrol that has proven useful in studying mechanisms involved in abnormal programming of various oestrogen target tissues during differentiation. Together, these data suggest new targets (i.e. adipocyte differentiation and mechanisms involved in weight homeostasis) of abnormal programming by EDCs, and provide evidence that support the scientific term 'the developmental origins of adult disease'. The emerging idea of an association of EDCs and obesity expands the focus on obesity from intervention and treatment to include prevention and avoidance of these chemical modifiers.
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Affiliation(s)
- Retha R Newbold
- Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, Division of Intramural Research, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
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Jefferson WN, Padilla-Banks E, Goulding EH, Williams CJ, Newbold RR. Neonatal Exposure to Genistein Adversely Affects MouseOocyte Developmental Competence. Biol Reprod 2008. [DOI: 10.1093/biolreprod/78.s1.84] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Ruhlen RL, Howdeshell KL, Mao J, Taylor JA, Bronson FH, Newbold RR, Welshons WV, vom Saal FS. Low phytoestrogen levels in feed increase fetal serum estradiol resulting in the "fetal estrogenization syndrome" and obesity in CD-1 mice. Environ Health Perspect 2008; 116:322-8. [PMID: 18335098 PMCID: PMC2265041 DOI: 10.1289/ehp.10448] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Accepted: 11/26/2007] [Indexed: 05/09/2023]
Abstract
BACKGROUND Although estrogenic chemicals can disrupt development of the reproductive system, there is debate about whether phytoestrogens in soy are beneficial, benign, or harmful. OBJECTIVES We compared reproductive and metabolic characteristics in male and female mice reared and maintained on non-soy low-phytoestrogen feed or soy-based high-phytoestrogen feed. METHODS The low-phytoestrogen diet was non-soy PMI 5K96 (verified casein diet), and the high-phytoestrogen diet consisted of soy-based PMI 5008 during pregnancy and lactation and soy-based PMI 5001 maintenance feed after weaning. RESULTS In fetuses whose mothers consumed the low-phytoestrogen PMI 5K96 feed, we found a paradoxical significant elevation in endogenous serum estradiol, which was associated postnatally with adverse reproductive outcomes referred to as the "fetal estrogenization syndrome (FES)". In females, this syndrome included early puberty and increased uterine responsiveness to estrogen, and in males, it included reduced testis, epididymis, and seminal vesicle size, but an enlarged prostate. The low-phytoestrogen-fed males and females were lighter at birth, but, between weaning and adulthood, they became obese and developed abnormally high serum leptin levels; these males, but not females, showed impaired glucose regulation. CONCLUSIONS Removing phytoestrogens from mouse feed produces an obese phenotype consistent with metabolic syndrome, and the associated reproductive system abnormalities are consistent with FES due to elevated endogenous fetal estradiol. Laboratory rodents may have become adapted to high-phytoestrogen intake over many generations of being fed soy-based commercial feed; removing all phytoestrogens from feed leads to alterations that could disrupt many types of biomedical research.
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Affiliation(s)
- Rachel L. Ruhlen
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, USA
| | - Kembra L. Howdeshell
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, USA
| | - Jiude Mao
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, USA
| | - Julia A. Taylor
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, USA
| | | | - Retha R. Newbold
- Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - Wade V. Welshons
- Department of Biomedical Sciences, University of Missouri-Columbia, Columbia, Missouri, USA
| | - Frederick S. vom Saal
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, USA
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Newbold RR, Jefferson WN, Grissom SF, Padilla-Banks E, Snyder RJ, Lobenhofer EK. Developmental exposure to diethylstilbestrol alters uterine gene expression that may be associated with uterine neoplasia later in life. Mol Carcinog 2007; 46:783-96. [PMID: 17394237 PMCID: PMC2254327 DOI: 10.1002/mc.20308] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Previously, we described a mouse model where the well-known reproductive carcinogen with estrogenic activity, diethylstilbestrol (DES), caused uterine adenocarcinoma following neonatal treatment. Tumor incidence was dose-dependent reaching >90% by 18 mo following neonatal treatment with 1000 microg/kg/d of DES. These tumors followed the initiation/promotion model of hormonal carcinogenesis with developmental exposure as initiator, and exposure to ovarian hormones at puberty as the promoter. To identify molecular pathways involved in DES-initiation events, uterine gene expression profiles were examined in prepubertal mice exposed to DES (1, 10, or 1000 microg/kg/d) on days 1-5 and compared to controls. Of more than 20 000 transcripts, approximately 3% were differentially expressed in at least one DES treatment group compared to controls; some transcripts demonstrated dose-responsiveness. Assessment of gene ontology annotation revealed alterations in genes associated with cell growth, differentiation, and adhesion. When expression profiles were compared to published studies of uteri from 5-d-old DES-treated mice, or adult mice treated with 17beta estradiol, similarities were seen suggesting persistent differential expression of estrogen responsive genes following developmental DES exposure. Moreover, several altered genes were identified in human uterine adenocarcinomas. Four altered genes [lactotransferrin (Ltf), transforming growth factor beta inducible (Tgfb1), cyclin D1 (Ccnd1), and secreted frizzled-related protein 4 (Sfrp4)], selected for real-time RT-PCR analysis, correlated well with the directionality of the microarray data. These data suggested altered gene expression profiles observed 2 wk after treatment ceased, were established at the time of developmental exposure and maybe related to the initiation events resulting in carcinogenesis.
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Affiliation(s)
- Retha R Newbold
- Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, NIEHS, Research Triangle Park, North Carolina 27709, USA
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Abstract
Dietary substances and xenobiotic compounds with hormone-like activity can disrupt the programming of endocrine signaling pathways that are established during perinatal differentiation. The consequences of this disruption may not be apparent until later in life but increasing evidence implicates developmental exposure to environmental hormone-mimics with a growing list of adverse health effects including reproductive problems and increased cancer risks. Obesity has recently been proposed to be yet another adverse health consequence of exposure to endocrine disrupting substances during development. There is a renewed focus on identifying contributions of environmental factors to the development of obesity since it is reaching worldwide epidemic proportions, and this disease has the potential to overwhelm healthcare systems with associated illnesses such as diabetes and cardiovascular disease. Here, we review the literature that proposes an association of perinatal exposure to endocrine disrupting chemicals, in particular those with estrogenic activity, with the development of obesity later in life. We further describe an animal model of developmental exposure to diethylstilbestrol (DES) to study mechanisms involved in programming for obesity. Our experimental data support the idea that adipocytes and the mechanisms involved in weight homeostasis are novel targets of abnormal programming of environmental estrogens, some of which are found in our foods as naturally occurring substances or inadvertently as contaminants.
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Affiliation(s)
- Retha R Newbold
- Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC, USA.
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Moore AB, Castro L, Yu L, Zheng X, Di X, Sifre MI, Kissling GE, Newbold RR, Bortner CD, Dixon D. Stimulatory and inhibitory effects of genistein on human uterine leiomyoma cell proliferation are influenced by the concentration. Hum Reprod 2007; 22:2623-31. [PMID: 17725991 PMCID: PMC2366995 DOI: 10.1093/humrep/dem185] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Due to dietary exposure of women to genistein, a soy-derived phytoestrogen, and the estrogen responsiveness of uterine leiomyomas 'fibroids', we evaluated the effects of genistein (0.001-50 microg/ml) on human uterine leiomyoma (UtLM) cells versus uterine smooth muscle cells (UtSMCs) in vitro. METHODS Light microscopy was used to determine the effects of genistein on cell morphology. Proliferation was assessed using a colorimetric assay and proliferating cell nuclear antigen (PCNA) immunocytochemistry. Flow cytometry was used to quantitate cells in the S-phase and those undergoing apoptosis. A fluorometric assay and confocal microscopy were used to detect caspase-3 activity and apoptotic bodies, respectively. RESULTS In UtLM cells, low concentrations (< or = 1 microg/ml) of genistein stimulated proliferation, increased PCNA labeling and the percentage of cells in the S-phase, but this did not occur in UtSMCs. Higher concentrations (> or = 10 microg/ml) of genistein adversely affected the morphology, significantly inhibited proliferation, decreased PCNA labeling, increased caspase-3 activity and induced apoptosis in both cell types. CONCLUSIONS Genistein's effects are concentration-dependent in both cell lines. Lower concentrations elicit proliferative effects on UtLM cells only; whereas, higher concentrations alter morphology, inhibit proliferation, and increase caspase activity and apoptosis in both cell types, with the latter two effects being more extensive in UtSMCs.
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Affiliation(s)
- A B Moore
- Comparative Pathobiology Group, Laboratory of Experimental Pathology, National Institute of Environmental Health Sciences, National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC 27709, USA
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Chen Y, Jefferson WN, Newbold RR, Padilla-Banks E, Pepling ME. Estradiol, progesterone, and genistein inhibit oocyte nest breakdown and primordial follicle assembly in the neonatal mouse ovary in vitro and in vivo. Endocrinology 2007; 148:3580-90. [PMID: 17446182 DOI: 10.1210/en.2007-0088] [Citation(s) in RCA: 205] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In developing mouse ovaries, oocytes develop as clusters of cells called nests or germ cell cysts. Shortly after birth, oocyte nests dissociate and granulosa cells surround individual oocytes forming primordial follicles. At the same time, two thirds of the oocytes die by apoptosis, but the link between oocyte nest breakdown and oocyte death is unclear. Although mechanisms controlling breakdown of nests into individual oocytes and selection of oocytes for survival are currently unknown, steroid hormones may play a role. Treatment of neonatal mice with natural or synthetic estrogens results in abnormal multiple oocyte follicles in adult ovaries. Neonatal genistein treatment inhibits nest breakdown suggesting multiple oocyte follicles are nests that did not break down. Here we investigated the role of estrogen signaling in nest breakdown and oocyte survival. We characterized an ovary organ culture system that recapitulates nest breakdown, reduction in oocyte number, primordial follicle assembly, and follicle growth in vitro. We found that estradiol, progesterone, and genistein inhibit nest breakdown and primordial follicle assembly but have no effect on oocyte number both in organ culture and in vivo. Fetal ovaries, removed from their normal environment of high levels of pregnancy hormones, underwent premature nest breakdown and oocyte loss that was rescued by addition of estradiol or progesterone. Our results implicate hormone signaling in ovarian differentiation with decreased estrogen and progesterone at birth as the primary signal to initiate oocyte nest breakdown and follicle assembly. These findings also provide insight into the mechanism of multiple oocyte follicle formation.
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Affiliation(s)
- Ying Chen
- Department of Biology, Syracuse University, 130 College Place, Syracuse, New York 13244, USA
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vom Saal FS, Akingbemi BT, Belcher SM, Birnbaum LS, Crain DA, Eriksen M, Farabollini F, Guillette LJ, Hauser R, Heindel JJ, Ho SM, Hunt PA, Iguchi T, Jobling S, Kanno J, Keri RA, Knudsen KE, Laufer H, LeBlanc GA, Marcus M, McLachlan JA, Myers JP, Nadal A, Newbold RR, Olea N, Prins GS, Richter CA, Rubin BS, Sonnenschein C, Soto AM, Talsness CE, Vandenbergh JG, Vandenberg LN, Walser-Kuntz DR, Watson CS, Welshons WV, Wetherill Y, Zoeller RT. Chapel Hill bisphenol A expert panel consensus statement: integration of mechanisms, effects in animals and potential to impact human health at current levels of exposure. Reprod Toxicol 2007; 24:131-8. [PMID: 17768031 PMCID: PMC2967230 DOI: 10.1016/j.reprotox.2007.07.005] [Citation(s) in RCA: 544] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Revised: 07/11/2007] [Accepted: 07/20/2007] [Indexed: 11/18/2022]
Affiliation(s)
| | - Benson T. Akingbemi
- Department of Anatomy, Physiology and Pharmacology, Auburn University, Auburn, AL 36849, United States
| | - Scott M. Belcher
- Department of Pharmacology and Cell Biophysics, Center for Environmental Genetics, University of Cincinnati, Cincinnati, OH 45267, United States
| | - Linda S. Birnbaum
- U.S. Environmental Protection Agency, Research Triangle Park, NC 27709, United States
| | - D. Andrew Crain
- Biology Department, Maryville College, Maryville, TN 37804, United States
| | - Marcus Eriksen
- Algalita Marine Research Foundation, Los Angeles, CA 90034, United States
| | | | - Louis J. Guillette
- Department of Zoology, University of Florida, Gainesville, FL 32611, United States
| | - Russ Hauser
- Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, United States
| | - Jerrold J. Heindel
- Division of Extramural Research and Training, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, United States
| | - Shuk-Mei Ho
- Department of Environmental Health, University of Cincinnati Medical School, Cincinnati, OH 45267, United States
| | - Patricia A. Hunt
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, United States
| | - Taisen Iguchi
- National Institutes of Natural Science, Okazaki Institute For Integrative Bioscience Bioenvironmental Science, Okazaki, Aichi 444-8787, Japan
| | - Susan Jobling
- Department of Biological Sciences, Brunel University, Uxbridge, Middlesex, UK
| | - Jun Kanno
- Division of Cellular & Molecular Toxicology, National Institute of Health Sciences, Tokyo 158-8501, Japan
| | - Ruth A. Keri
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Karen E. Knudsen
- Department of Cell and Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, United States
| | - Hans Laufer
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, United States
| | - Gerald A. LeBlanc
- Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695, United States
| | - Michele Marcus
- Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA 30322, United States
| | - John A. McLachlan
- Center for Bioenvironmental Research, Tulane and Xavier Universities, New Orleans, LA 70112, United States
| | | | - Angel Nadal
- Instituto de Bioingeniería, Universidad Miguel Hernández, Elche 03202, Alicante, Spain
| | - Retha R. Newbold
- Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, United States
| | - Nicolas Olea
- CIBERESP Hospital Clinico-University of Granada, 18071 Granada, Spain
| | - Gail S. Prins
- Department of Urology, University of Illinois at Chicago, Chicago, IL 60612, United States
| | | | - Beverly S. Rubin
- Department of Anatomy and Cellular Biology, Tufts Medical School, Boston, MA 02111, United States
| | - Carlos Sonnenschein
- Department of Anatomy and Cellular Biology, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Ana M. Soto
- Department of Anatomy and Cell Biology, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Chris E. Talsness
- Charité University Medical School Berlin, Campus Benjamin Franklin, Institute of Clinical Pharmacology and Toxicology, Department of Toxicology, 14195 Berlin, Germany
| | - John G. Vandenbergh
- Department of Zoology, North Carolina State University, Raleigh, NC 27695, United States
| | - Laura N. Vandenberg
- Tufts University Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, United States
| | | | - Cheryl S. Watson
- Biochemistry and Molecular Biology Department, University of Texas Medical Branch, Galveston, TX 77555, United States
| | - Wade V. Welshons
- Department of Biomedical Sciences, University of Missouri, Columbia, MO 65211, United States
| | - Yelena Wetherill
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, United States
| | - R. Thomas Zoeller
- Biology Department, University of Massachusetts, Amherst, MA 01003, United States
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Newbold RR, Jefferson WN, Padilla-Banks E. Long-term adverse effects of neonatal exposure to bisphenol A on the murine female reproductive tract. Reprod Toxicol 2007; 24:253-8. [PMID: 17804194 PMCID: PMC2043380 DOI: 10.1016/j.reprotox.2007.07.006] [Citation(s) in RCA: 194] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 07/10/2007] [Accepted: 07/23/2007] [Indexed: 11/20/2022]
Abstract
The developing fetus is uniquely sensitive to perturbation by chemicals with hormone-like activity. The adverse effects of prenatal diethylstilbestrol (DES) exposure are a classic example. Since concern has been mounting regarding the human health and environmental effects of bisphenol A (BPA), a high-production-volume chemical with estrogenic activity used in the synthesis of plastics, we investigated its long-term effects in an experimental animal model that was previously shown useful in studying the adverse effects of developmental exposure to DES. Outbred female CD-1 mice were treated on days 1-5 with subcutaneous injections of BPA (10, 100 or 1000 microg/kg/day) dissolved in corn oil or corn oil alone (Control). At 18 months, ovaries and reproductive tract tissues were examined. There was a statistically significant increase in cystic ovaries and cystic endometrial hyperplasia (CEH) in the BPA-100 group as compared to Controls. Progressive proliferative lesion (PPL) of the oviduct and cystic mesonephric (Wolffian) duct remnants were also seen in all of the BPA groups. More severe pathologies of the uterus following neonatal BPA treatment included adenomyosis, leiomyomas, atypical hyperplasia, and stromal polyps. These data suggest that BPA causes long-term adverse effects if exposure occurs during critical periods of differentiation.
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Affiliation(s)
- Retha R Newbold
- Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC 27709, USA.
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39
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Jefferson WN, Padilla-Banks E, Newbold RR. Disruption of the developing female reproductive system by phytoestrogens: Genistein as an example. Mol Nutr Food Res 2007; 51:832-44. [PMID: 17604387 DOI: 10.1002/mnfr.200600258] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Studies in our laboratory have shown that exposure to genistein causes deleterious effects on the developing female reproductive system. Mice treated neonatally on days 1-5 by subcutaneous injection of genistein (0.5-50 mg/kg) exhibited altered ovarian differentiation leading to multioocyte follicles (MOFs) at 2 months of age. Ovarian function and estrous cyclicity were also disrupted by neonatal exposure to genistein with increasing severity observed over time. Reduced fertility was observed in mice treated with genistein (0.5, 5, or 25 mg/kg) and infertility was observed at 50 mg/kg. Mammary gland and behavioral endpoints were also affected by neonatal genistein treatment. Further, transgenerational effects were observed; female offspring obtained from breeding genistein treated females (25 mg/kg) to control males had increased MOFs. Thus, neonatal treatment with genistein at environmentally relevant doses caused adverse consequences on female development which is manifested in adulthood. Whether adverse effects occur in human infants exposed to soy-based products such as soy infant formulas is unknown but the neonatal murine model may help address some of the current uncertainties since we have shown that many effects obtained from feeding genistin, the glycosolated form of genistein found in soy formula, are similar to those obtained from injecting genistein.
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Affiliation(s)
- Wendy N Jefferson
- Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC, USA.
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40
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Richter CA, Birnbaum LS, Farabollini F, Newbold RR, Rubin BS, Talsness CE, Vandenbergh JG, Walser-Kuntz DR, vom Saal FS. In vivo effects of bisphenol A in laboratory rodent studies. Reprod Toxicol 2007; 24:199-224. [PMID: 17683900 PMCID: PMC2151845 DOI: 10.1016/j.reprotox.2007.06.004] [Citation(s) in RCA: 809] [Impact Index Per Article: 47.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Revised: 06/06/2007] [Accepted: 06/11/2007] [Indexed: 12/25/2022]
Abstract
Concern is mounting regarding the human health and environmental effects of bisphenol A (BPA), a high-production-volume chemical used in synthesis of plastics. We have reviewed the growing literature on effects of low doses of BPA, below 50 mg/(kg day), in laboratory exposures with mammalian model organisms. Many, but not all, effects of BPA are similar to effects seen in response to the model estrogens diethylstilbestrol and ethinylestradiol. For most effects, the potency of BPA is approximately 10-1000-fold less than that of diethylstilbestrol or ethinylestradiol. Based on our review of the literature, a consensus was reached regarding our level of confidence that particular outcomes occur in response to low dose BPA exposure. We are confident that adult exposure to BPA affects the male reproductive tract, and that long lasting, organizational effects in response to developmental exposure to BPA occur in the brain, the male reproductive system, and metabolic processes. We consider it likely, but requiring further confirmation, that adult exposure to BPA affects the brain, the female reproductive system, and the immune system, and that developmental effects occur in the female reproductive system.
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Affiliation(s)
| | | | | | - Retha R. Newbold
- National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC
| | - Beverly S. Rubin
- Department of Anatomy and Cell Biology, Tufts University School of Medicine, Boston, MA
| | - Chris E. Talsness
- Institute of Clinical Pharmacology and Toxicology, Charité Universitätsmedizin Berlin, Berlin, Germany
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41
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Newbold RR, Padilla-Banks E, Snyder RJ, Phillips TM, Jefferson WN. Developmental exposure to endocrine disruptors and the obesity epidemic. Reprod Toxicol 2007; 23:290-6. [PMID: 17321108 PMCID: PMC1931509 DOI: 10.1016/j.reprotox.2006.12.010] [Citation(s) in RCA: 161] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Revised: 12/20/2006] [Accepted: 12/20/2006] [Indexed: 12/25/2022]
Abstract
Xenobiotic and dietary compounds with hormone-like activity can disrupt endocrine signaling pathways that play important roles during perinatal differentiation and result in alterations that are not apparent until later in life. Evidence implicates developmental exposure to environmental hormone-mimics with a growing list of health problems. Obesity is currently receiving needed attention since it has potential to overwhelm health systems worldwide with associated illnesses such as diabetes and cardiovascular disease. Here, we review the literature that proposes an association of exposure to environmental endocrine disrupting chemicals with the development of obesity. We describe an animal model of developmental exposure to diethylstilbestrol (DES), a potent perinatal endocrine disruptor with estrogenic activity, to study mechanisms involved in programming an organism for obesity. This experimental animal model provides an example of the growing scientific field termed "the developmental origins of adult disease" and suggests new targets of abnormal programming by endocrine disrupting chemicals.
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Affiliation(s)
- Retha R Newbold
- Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, Mail-Drop E4-02, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC 27709, United States.
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42
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Jefferson WN, Padilla-Banks E, Newbold RR. Disruption of the female reproductive system by the phytoestrogen genistein. Reprod Toxicol 2006; 23:308-16. [PMID: 17250991 DOI: 10.1016/j.reprotox.2006.11.012] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Accepted: 11/20/2006] [Indexed: 11/26/2022]
Abstract
Studies in our laboratory have shown that developmental exposure to genistein causes deleterious effects on the reproductive system. Oral exposure to genistin (25mg/kg) increases uterine weight at 5 days of age similar to subcutaneous injection of genistein (20mg/kg) suggesting that subcutaneous injection of genistein is a suitable model for oral exposure to genistin. Mice treated neonatally by subcutaneous injection of genistein (0.5-50mg/kg) exhibit altered ovarian differentiation leading to multi-oocyte follicles (MOFs). Ovarian function and estrous cyclicity were disrupted in genistein treated mice with increasing severity over time. Reduced fertility was observed in mice treated with genistein (0.5, 5, or 25mg/kg) and infertility was observed at 50mg/kg. Females generated from genistein 25mg/kg females bred to control males have increased MOFs suggesting these effects can be transmitted to subsequent generations. Thus, neonatal treatment with genistein at environmentally relevant doses caused adverse consequences on reproduction in adulthood.
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Affiliation(s)
- Wendy N Jefferson
- Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, NIH, DHHS, PO Box 12233, Research Triangle Park, NC 27709, United States.
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43
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Padilla-Banks E, Jefferson WN, Newbold RR. Neonatal exposure to the phytoestrogen genistein alters mammary gland growth and developmental programming of hormone receptor levels. Endocrinology 2006; 147:4871-82. [PMID: 16857750 DOI: 10.1210/en.2006-0389] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Developmental effects of genistein (Gen) on the mammary gland were investigated using outbred female CD-1 mice treated neonatally on d 1-5 by sc injections at doses of 0.5, 5, or 50 mg/kg.d. Examination of mammary gland whole mounts (no. 4) before puberty (4 wk) revealed no morphological differences in development after Gen treatment. However, mice treated with Gen-50 had stunted development characterized by less branching at 5 wk and decreased numbers of terminal end buds at 5 and 6 wk. Conversely, at 6 wk, Gen-0.5-treated mice exhibited advanced development with increased ductal elongation compared with controls. Measurements of hormone receptor levels showed increased levels of progesterone receptor protein and estrogen receptor-beta mRNA in Gen-0.5-treated mice compared with controls; ERalpha expression was decreased after all doses of Gen treatment. Lactation ability, measured by pup weight gain and survival, was not affected after neonatal Gen-0.5 and Gen-5. Mice treated with Gen-50 did not deliver live pups; therefore, lactation ability could not be determined. Evaluation of mammary glands in aged mice (9 months) showed no differences between Gen-0.5-treated mice and controls but mice treated with Gen-5 and Gen-50 exhibited altered morphology including reduced lobular alveolar development, dilated ducts, and focal areas of "beaded" ducts lined with hyperplastic ductal epithelium. In summary, neonatal Gen exposure altered mammary gland growth and development as well as hormone receptor levels at all doses examined; higher doses of Gen led to permanent long-lasting morphological changes.
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Affiliation(s)
- Elizabeth Padilla-Banks
- Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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44
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Jefferson WN, Padilla-Banks E, Newbold RR. Studies of the effects of neonatal exposure to genistein on the developing female reproductive system. J AOAC Int 2006; 89:1189-96. [PMID: 16918037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Studies have shown that developmental exposure to genistein alters murine reproductive differentiation, resulting in abnormal ovarian development (multioocyte follicles) and uterine neoplasia later in life. Further, reproductive function was altered. Prolonged estrous cyclicity was observed following neonatal genistein treatment (0.5-50 mg/kg) on Days 1-5 with dose- and age-related increase in severity. Fertility, determined at 2, 4, and 6 months, showed decreased numbers of genistein-treated females (0.5 or 5 mg/kg) delivering live pups and reduced numbers of pups. At 6 months, 60% of 0.5 mg/kg and 40% of 5 mg/kg groups delivered live pups compared to 100% of controls. At 2 months, half the mice treated with 25 mg/kg of genistein and none treated with 50 mg/kg delivered live pups, although half of the latter group showed signs of pregnancy with few small implantation sites. Ovarian function was disrupted in the low genistein-dosed mice with increased numbers of corpora lutea (CLs) compared to controls and increased ovulated oocytes following exogenous gonadotropins treatment. In contrast, mice treated with high genistein doses had decreased numbers of CLs; ovulation could be restored with exogenous gonadotropins. Thus, neonatal treatment with genistein at environmentally relevant doses caused adverse consequences on ovarian development and reproductive function.
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Affiliation(s)
- Wendy N Jefferson
- National Institute of Environmental Health Sciences, NIH, DHHS, Developmental Endocrinology and Endocrine Disruptor Section, Laboratory of Molecular Toxicology, Research Triangle Park, NC 27709, USA.
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Abstract
The synthetic estrogen diethylstilbestrol (DES) is a potent perinatal endocrine disruptor. In humans and experimental animals, exposure to DES during critical periods of reproductive tract differentiation permanently alters estrogen target tissues and results in long-term abnormalities such as uterine neoplasia that are not manifested until later in life. Using the developmentally exposed DES mouse, multiple mechanisms have been identified that play a role in its carcinogenic and toxic effects. Analysis of the DES murine uterus reveals altered gene expression pathways that include an estrogen-regulated component. Thus, perinatal DES exposure, especially at low doses, offers the opportunity to study effects caused by weaker environmental estrogens and provides an example of the emerging scientific field termed the developmental origin of adult disease. As a model endocrine disruptor, it is of particular interest that even low doses of DES increase uterine tumor incidence. Additional studies have verified that DES is not unique; when other environmental estrogens are tested at equal estrogenic doses, developmental exposure results in increased incidence of uterine neoplasia similar to that caused by DES. Interestingly, our data suggest that this increased susceptibility for tumors is passed on from the maternal lineage to subsequent generations of male and female descendants; the mechanisms involved in these transgenerational events include genetic and epigenetic events. Together, our data point out the unique sensitivity of the developing organism to endocrine-disrupting chemicals, the occurrence of long-term effects after developmental exposure, and the possibility for adverse effects to be transmitted to subsequent generations.
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Affiliation(s)
- Retha R Newbold
- Developmental Endocrinology and Endocrine Disruptor Section, Mail-Drop E4-02, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
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46
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Doerge DR, Twaddle NC, Churchwell MI, Newbold RR, Delclos KB. Lactational transfer of the soy isoflavone, genistein, in Sprague-Dawley rats consuming dietary genistein. Reprod Toxicol 2005; 21:307-12. [PMID: 16257506 DOI: 10.1016/j.reprotox.2005.09.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2005] [Revised: 08/15/2005] [Accepted: 09/13/2005] [Indexed: 10/25/2022]
Abstract
Exposures of Sprague-Dawley rats to the soy isoflavone, genistein, throughout the entire lifespan have produced a number of effects on reproductive tissues, immune function, neuroendocrine function and behavior. Our previous studies investigated pharmacokinetics and disposition of genistein during adult and fetal periods and this study describes the internal exposures of post-natal day 10 (PND10) rat pups due to lactational transfer of genistein. Conjugated and aglycone forms of genistein were measured by using LC/MS/MS in serum (PND10) and milk (PND7) from lactating dams consuming a genistein-fortified soy-free diet, and in serum from their pups at a time when milk was the only food source (PND10). This study shows that limited lactational transfer of genistein to rat pups occurs and that internal exposures to the active aglycone form of genistein are generally lower than those measured previously in the fetal period. These results suggest that developmental effects attributable to genistein exposure in our chronic and multi-generation studies are more likely to result from fetal exposures because of the higher levels of the active estrogenic aglycone form of genistein in utero, although the possibility of neonatal responses cannot be excluded.
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Affiliation(s)
- Daniel R Doerge
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
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Guo TL, Germolec DR, Musgrove DL, Delclos KB, Newbold RR, Weis C, White KL. Myelotoxicity in genistein-, nonylphenol-, methoxychlor-, vinclozolin- or ethinyl estradiol-exposed F1 generations of Sprague–Dawley rats following developmental and adult exposures. Toxicology 2005; 211:207-19. [PMID: 15925024 DOI: 10.1016/j.tox.2005.03.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2004] [Revised: 01/13/2005] [Accepted: 03/16/2005] [Indexed: 11/18/2022]
Abstract
The myelotoxicity of five endocrine active chemicals was evaluated in F1 generation of Sprague-Dawley rats following developmental and adult exposures at three concentration levels. Rats were exposed to genistein (GEN: 25, 250 and 1250 ppm), nonylphenol (NPH: 25, 500 and 2000 ppm), methoxychlor (MXC: 10, 100 and 1000 ppm), vinclozolin (VCZ: 10, 150 and 750 ppm) and ethinyl estradiol (EE2: 5, 25 and 200 ppb) gestationally and lactationally through dams from day 7 of gestation and through feed after weaning on postnatal day (PND) 22 to PND 64. The parameters examined included the number of recovered bone marrow cells, DNA synthesis, and colony forming units (CFU) in the presence of granulocyte macrophage-colony stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF) and erythropoietin. Except for the EE2, the concentrations of other individual chemicals in the diet were in an approximate range that allowed for a comparison to be made in terms of myelotoxic potency. Decreases in the DNA synthesis, CFU-GM and CFU-M seemed to be the common findings among the alterations induced by these compounds. Using the numbers of alterations induced by each chemical in the parameters examined as criteria for comparison, the order of myelotoxic potency in F(1) males was: GEN>MXC>NPH>VCZ; the order in females: GEN>NPH>VCZ. Additionally, some of the functional changes induced by these compounds were gender-specific or dimorphic. Overall, the results demonstrated that developmental and adult exposures of F1 rats to these endocrine active chemicals at the concentrations tested had varied degrees of myelotoxicity with GEN being the most potent. Furthermore, the sex-specific effects of these chemicals in F1 male and female rats suggest that there may be interactions between these compounds and sex hormone in modulating these responses.
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Affiliation(s)
- T L Guo
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, P.O. Box 980613, Richmond, VA 23298-0613, USA.
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Affiliation(s)
- Retha R Newbold
- Developmental Endocrinology Section, Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
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Jefferson WN, Padilla-Banks E, Newbold RR. Adverse effects on female development and reproduction in CD-1 mice following neonatal exposure to the phytoestrogen genistein at environmentally relevant doses. Biol Reprod 2005; 73:798-806. [PMID: 15930323 DOI: 10.1095/biolreprod.105.041277] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Outbred female CD-1 mice were treated with genistein (Gen), the primary phytoestrogen in soy, by s.c. injections on Neonatal Days 1-5 at doses of 0.5, 5, or 50 mg/kg per day (Gen-0.5, Gen-5, and Gen-50). The day of vaginal opening was observed in mice treated with Gen and compared with controls, and although there were some differences, they were not statistically significant. Gen-treated mice had prolonged estrous cycles with a dose- and age-related increase in severity of abnormal cycles. Females treated with Gen-0.5 or Gen-5 bred to control males at 2, 4, and 6 mo showed statistically significant decreases in the number of live pups over time with increasing dose; at 6 mo, 60% of the females in the Gen-0.5 group and 40% in the Gen-5 group delivered live pups compared with 100% of controls. Mice treated with Gen-50 did not deliver live pups. At 2 mo, >60% of the mice treated with Gen-50 were fertile as determined by uterine implantation sites, but pregnancy was not maintained; pregnancy loss was characterized by fewer, smaller implantation sites and increased reabsorptions. Mice treated with lower doses of Gen had increased numbers of corpora lutea compared with controls, while mice treated with the highest dose had decreased numbers; however, superovulation with eCG/hCG yielded similar numbers of oocytes as controls. Serum levels of progesterone, estradiol, and testosterone were similar between Gen-treated and control mice when measured before puberty and during pregnancy. In summary, neonatal treatment with Gen caused abnormal estrous cycles, altered ovarian function, early reproductive senescence, and subfertility/infertility at environmentally relevant doses.
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Affiliation(s)
- Wendy N Jefferson
- Developmental Endocrinology Section, Laboratory of Molecular Toxicology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
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Flynn KM, Delclos KB, Newbold RR, Ferguson SA. Long term dietary methoxychlor exposure in rats increases sodium solution consumption but has few effects on other sexually dimorphic behaviors. Food Chem Toxicol 2005; 43:1345-54. [PMID: 15989973 DOI: 10.1016/j.fct.2005.03.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2004] [Revised: 03/03/2005] [Accepted: 03/11/2005] [Indexed: 11/18/2022]
Abstract
Methoxychlor is an insecticide with estrogen-like activity, thus exposure during development might cause sexually dimorphic behavioral alterations. To evaluate this, pregnant rats consumed diets containing 0, 10, 100 or 1000 ppm methoxychlor from gestational day 7, and offspring continued on these diets until postnatal day (PND) 77. Assessments of sexually dimorphic behaviors in offspring indicated that intake of a 3.0% sodium chloride solution was significantly increased (41%) in males and females of the 1000 ppm group. No treatment group differed from controls in open field nor running wheel activity, play behavior, nor 0.3% saccharin solution intake. Offspring of the 1000 ppm group showed significantly decreased body weight, reaching 17% less than controls at PND 77, but not clearly related to their salt solution intake. During pregnancy, 1000 ppm dams consumed 23% less food and weighed 10% less than controls, but this did not affect litter outcomes. These results indicate that in rodents, developmental and chronic exposure to dietary methoxychlor alters the sexually dimorphic behavior of salt-solution intake in young adults of both sexes. Similar behavioral alterations with other xenoestrogens, and the potential for interactions among xenoestrogens, suggest that this report may minimize the true effects of dietary methoxychlor exposure.
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Affiliation(s)
- K M Flynn
- Division of Neurotoxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA.
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