Environmental Endocrinology

by

Sean C. Lema

• LAST REVIEWED: 27 April 2017
• LAST MODIFIED: 27 April 2017
• DOI: 10.1093/obo/9780199363445-0066

Introduction

Environmental endocrinology is the study of how the environmental conditions experienced by an organism affect the endocrine system, as well as how the endocrine system regulates the interactions of organisms (e.g., behavior) with their environments. The endocrine system comprises all of the tissues and glands in the body that synthesize and release chemical-signaling molecules referred to as hormones. Hormones are made by specific glands, including the pituitary gland, hypothalamus, thyroid gland, adrenal glands, pancreas, parathyroid glands, ovaries, testes, and pineal gland. Several other tissues in the body, including the gastrointestinal tract, adipose cells, and bone, also produce hormones, although these tissues have not traditionally been categorized as endocrine glands. Hormones released from these glands and tissues are transported throughout the body, often via blood circulation, to have molecular, cellular, or physiological effects on other tissues expressing receptor proteins specific for a given hormone. While the study of environmental endocrinology encompasses understanding how hormone signaling pathways are affected by environmental conditions broadly, research in this scientific field has traditionally been partitioned into questions focusing either on the effects of physical conditions (e.g., temperature, day length, water salinity) and the social environment (see Endocrine Responses to Environmental Variation) or on the inappropriate modulation of hormone signaling pathways by environmental or dietary exposure to man-made synthetic chemicals (see also Endocrine-Disrupting Chemicals). While the name environmental endocrinology is sometimes considered synonymous with the study of hormonally active chemical compounds, recent research efforts have begun to ask how the effects of synthetic chemical exposure on hormone signaling are dependent on environmental context. With the continuing decline and loss of biodiversity worldwide, there is also a growing use of endocrine methods in the conservation and management of imperiled species (see also Conservation Endocrinology).

General Overviews

Several published works provide historical perspectives or overviews of subdisciplines within the scientific field of environmental endocrinology. Bradshaw 2007 presents a historical review of the study of environmental influences on hormone signaling and outlines a modern perspective on how research in nonhuman, comparative animals can inform basic questions about the functional and evolutionary diversity of the endocrine system. Wingfield 2008 reviews how hormone studies are increasingly needed to understand how organisms are responding to rapidly changing environments in the face of human disturbance and a shifting global climate. Colborn, et al. 1993 provides one of the first compilations of evidence that man-made chemicals may disrupt the normal development and function of reproductive, immune, and endocrine systems. Colborn, et al. 1996 is a landmark book that offers an accessible compilation of the evidence that man-made, endocrine-disrupting chemicals (EDCs) can subtly alter physiology, development, and behavior, and advocates that such effects may impact the health and survival of wildlife populations and ourselves. A more up-to-date summary of the evidence for man-made synthetic chemicals acting as endocrine disruptors can be found in Khetan 2014. Demeneix 2014 addresses whether the mental health and intelligence of children is being impacted by in utero exposure to chemical pollutants that have endocrine-active properties and disrupt thyroid hormone signaling. Walker, et al. 2005 reviews how field endocrinology techniques can be informative for conservation biology and details an example wherein the measurement of glucocorticoid hormones was used to identify unseen stressors for wildlife.

• Bradshaw, Don. 2007. Environmental endocrinology. General and Comparative Endocrinology 152:125–141.

  DOI: 10.1016/j.ygcen.2006.12.026

  Provides a historical overview of the field application of endocrine methods to the study of wildlife. Also presents specific examples on stress physiology in Arctic birds and reproductive endocrinology in a marsupial mouse.

• Colborn, Theo, Dianne Dumanoski, and John Peterson Myers. 1996. Our stolen future: are we threatening our fertility, intelligence, and survival? A scientific detective story. New York: Penguin.

  Considered the most impactful work in the science of endocrine disruption. Provides the initial compilation of evidence for synthetic chemicals in the environment disrupting the hormone signaling pathways of wildlife and humans. Arguably, the publication of this book served as a catalyst for increased public awareness and research on endocrine disruption by man-made chemical pollutants.

• Colborn, Theo, Frederick S. vom Saal, and Ana M. Soto. 1993. Developmental effects of endocrine-disrupting chemicals in wildlife and humans. Environmental Health Perspectives 101:378–384.

  DOI: 10.1289/ehp.93101378

  A groundbreaking review paper outlining the evidence that man-made chemicals can disrupt endocrine function in laboratory animals and wildlife.

• Demeneix, Barbara. 2014. Losing our minds: How environmental pollution impairs human intelligence and mental health. New York: Oxford Univ. Press.

  DOI: 10.1093/acprof:oso/9780199917518.001.0001

  Summarizes the accumulating evidence that exposure to environmental chemical pollution may be impairing thyroid hormone signaling in humans. This work focuses attention on whether such pollution-induced disruption to thyroid hormone pathways may be impacting neurological development in unborn children and placing people at elevated risk for behavioral and mental disorders.

• Khetan, Sushil K. 2014. Endocrine disruptors in the environment. Hoboken, NJ: John Wiley.

  DOI: 10.1002/9781118891094

  Provides a review of the scientific evidence that some man-made synthetic chemicals interfere with the production, release, transport, metabolism, or elimination of endogenously synthesized hormones in wildlife and humans. Addresses the mechanisms of action for endocrine disruption, as well as the regulatory and policy implications of endocrine disruptors.

• Walker, Brian G., Dee P. Boersma, and John C. Wingfield. 2005. Field endocrinology and conservation biology. Integrative and Comparative Biology 45:12–18.

  DOI: 10.1093/icb/45.1.12

  This paper provides an overview of how measuring hormone concentrations in wildlife in the field can provide insights into unseen stressors experienced by wildlife and, ultimately, inform challenges in wildlife conservation.

• Wingfield, John C. 2008. Comparative endocrinology, environment and global change. General and Comparative Endocrinology 157:207–216.

  DOI: 10.1016/j.ygcen.2008.04.017

  Outlines the importance of comparative endocrinology for evaluating how wildlife are responding to a changing world as a result of chemical pollution, habitat degradation, and disturbance, biodiversity loss, and climate change.