Analysis Of Environmental Endocrine Disruptors

Addresses many aspects of endocrine disruption by environmental encountered toxic substances. Initial chapters provide essential background information whilst later chapters address specific aspects of endocrine disrupting contaminants (EDC)

From 11 to 15 July 1977 about 60 physiologists, endo crinologists, ecologists and other biologists from 14 countries convened at the University Montpellier for a symposium on Environmental Endocrinology. This meet ing was organized as a Satellite Symposium of the 27th International Congress of Physiological Sciences, Paris, 18-23 July 1977. This volume is a record of the com munications presented at the symposium. The objectives of the program were to examine the role of the endocrine system in a wide spectrum of adjustments and adaptations to changes in environmental conditions by various spe cies of animals, including man, and to promote an ex change of ideas among investigators who have approached these functions from diverse aspects. The diversity of the information and ideas communicated is great. Of necessity, they represent only an extremely modest se lection of the many facets of endocrine function in the interaction of animals with their environments. Be yond the usefulness of the communications individually, we hope that they collectively demonstrate the substan tial heuristic value of the concept of environmental endocrinology as it was perceived by the participants. We acknowledge gratefully the kindness and sympathy of Professor Jaques ROUZAUD, President of the University of Montpellier II, for his generous extension of the hospitality of the University to the Symposium. We are most grateful to Mrs. Monique VIEU who effected so well the secretarial organization of the Sympos.

This book originated in a series of cross-disciplinary conversations in the years 1984-1990 between the editor, who is a physician-researcher involved in clinical and laboratory research, and a dioxin toxicologist. During the years in which the conversations took place, an extraordinary amount of new scientific literature was published related to dioxins, defined for purposes of this text as the chlorinated dibenzo-p-dioxins, dibenzofurans, polychlorinated biphe nyls (PCB's) and other compounds that are structurally and toxicologically similar to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7 ,8-TCDD), the most extensively studied and most toxic of this group of chemicals. Dioxins also began to interest not only chemists and toxicologists, but also specialists from diverse disciplines such as wildlife and environmental science, immunology, neuroscience,public health, epidemiology, med icine, government, law, sociology, and journalism. Specialists from such varied disciplines, while familiar with their own literature, frequently did not have time to follow the dioxin literature outside their specialty area. In addition, each specialty had unique knowledge, methods, and perspectives. Cross disciplinary conversation was necessary, but all too frequently, specialists from the various disciplines did not speak the same language, resulting in misunderstanding.

This book describes how exposure to various classes of endocrine disruptors, as well as other environmental chemicals targeting the endocrine system by alternative non-endocrine mechanisms, impact on endocrinological and endocrinological-related diseases. It includes comprehensive reviews of all aspects of environmental endocrinology, ranging from sources and patterns of exposure and identification of endocrine targets to direct endocrine disruptive mechanisms and indirect actions on the endocrine system, the latter including endocrine cell-directed cytotoxicity, oxidative damage, and genetic and epigenetic aberrations resulting in endocrine damage. It also examines the causal pathways and offers an extensive overview of downstream endocrinological and endocrinological-related disorders. In addition, several chapters focus on transgenerational actions, which are a topic of particular interest. Lastly, evidence from preclinical and clinical studies provides the basis for an in-depth, critical discussion of each topic. The book is part of the SpringerReference program, which provides access to ‘living editions’ that are constantly updated using a dynamic peer-review publishing process.

Potential health effects from chemicals that disrupt endocrine function pose an environmental health concern because of their ability to interfere with normal hormone function in human and wildlife populations. The endocrine system regulates biological processes throughout the body and is sensitive to small changes in hormone concentrations. Endocrine-disruptor research has focused primarily on chemicals that affect three hormone pathways that play important roles in reproduction and development - the estrogen, androgen, and thyroid hormone pathways. Some of this research has identified dose-response relationships that have nonmonotonic curves. Nonmonotonic dose-response curves (NMDRs) are of concern because they do not follow the usual assumption made in toxicology that as dose decreases the response also decreases. The existence of NMDRs has been a controversial topic for decades, and there has been considerable debate about their implications for how chemicals are tested and for how risks from such chemicals are assessed. Toxicity tests are designed to identify hazards and to characterize dose-response relationships, so tests are aimed at finding a (high) dose that elicits a response, and dose-response is explored by testing lower doses spaced to identify statistically a no- or lowest-observed-adverse-effect level. The concern for NMDRs is that such studies, as currently designed, might not detect the inflection of the dose-response curve if only a few doses are tested or if the change in inflection occurs below the range of doses tested. Another concern is that some NMDRs are found for biological effects that are not usually evaluated in toxicity tests. If current testing strategies are inadequate to account for NMDRs, changes to risk assessment practices might be necessary. To help address these issues, the U.S. Environmental Protection Agency (EPA) developed a draft State-of-the-Science Evaluation: Nonmonotonic Dose Responses as they Apply to Estrogen, Androgen, and Thyroid Pathways and EPA Testing and Assessment Procedures. EPA asked the National Research Council to conduct an independent review of this evaluation to ensure that it is scientifically sound and of high quality. Review of Environmental Protection Agency's State-of-the-Science Evaluation of Nonmonotonic Dose-Response as they Apply to Endocrine Disrupters evaluates whether EPA's evaluation presents a scientifically sound and high-quality analysis of the literature on NMDRs. This report reviews how well the EPA evaluation described how the assessment was performed, whether consistent methods and criteria were applied in the analysis of different evidence streams, and whether appropriate methods were applied to evaluating the evidence. The report makes recommendations to improve EPA's process and strengthen the evaluation.

This database, available in print and electronic form, provides information on chemical, physical, and toxicological properties of known and suspected environmental endocrine disruptors in a convenient easy-to-use format. Much of the research on EEDs has focused on the effects of these chemicals on wildlife, linking certain compounds to birth defects and abnormal development of immune and reproductive systems.