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Can Chemicals in the Environment That Affect Hormone Function Disrupt Development?
Citation:
KAVLOCK, R. J. Can Chemicals in the Environment That Affect Hormone Function Disrupt Development? Second Edition, Chapter 27, Barbara Hales; Anthony Scialli; Melissa S. Tassinari (ed.), Teratology Primer. John Wiley & Sons Incorporated, New York, NY, 1(2):71-72, (2010).
Impact/Purpose:
Organizations that have reviewed the evidence concerning the impact of endocrine disruptors in the environment on human health have generally concluded that additional research is needed before cause-and-effect determinations can be made with any degree of confidence. The link between exposure to endocrine disruptors and effects in humans is largely based on the concurrent rise in the use of many chemicals with hormonal activity and the increase over time in certain health outcomes that have at least a partial endocrine basis. However, data on the impact of low level environmental exposures on the rates of endocrine-sensitive health outcomes have been conflicting and there are some who do not believe that human endocrine disorders are caused by low level environmental exposures. The Endocrine Society was one of the most recent organizations to weigh in on the controversy, when it released a position paper that made a number of recommendations regarding research to increase our understanding of the effects of endocrine active chemicals and advocated involvement of individual and scientific society stakeholders in fostering changes in public policy and awareness of the issue.
Description:
Hormones, including estrogens and androgens, regulate the expression of genes that play critical roles in guiding the development of organ systems in the embryo. Changes in either the amount or the timing of hormone exposure can lead to altered human development. For example, humans with a defect in the androgen receptor gene have androgen insensitivity syndrome; although they are genetically male, they look female, because androgens cannot activate the receptor to masculinize the reproductive tract during critical periods of prenatal development. Hormonally-active chemicals were first shown to have effects on development in humans in the early 1970s, when vaginal adenocarcinoma, a rare cancer, was shown to be linked to fetal exposure to diethylstilbestrol (DES). During the 1950s, the mothers of these young women had been given DES, a synthetic estrogen, in an effort to prevent miscarriage and preterm delivery. In Taiwan in 1979, many people consumed rice oil contaminated with high levels of polychlorinated biphenyls (PCBs) and dibenzofurans. The offspring of exposed women were smaller at birth and had delays in neurological development. Several more recent studies on PCBs have shown neurological effects in other populations exposed to lower amounts. Although we know that PCBs and related compounds can interact with various components of the endocrine system, the exact cause for the developmental disorders observed after these exposures is not known. In 1992, a publication of the proceedings of a conference organized by Theo Colborn concluded, “We are certain of the following:...A large number of man-made chemicals that have been released into the environment... have the potential to disrupt endocrine systems of animals, including humans”.
