The endocrine system is one of the body’s main communication networks. It produces hormones that direct communication and coordinate functions among tissues throughout the body. The ovaries, testes, adrenal glands, thyroid, pituitary gland, liver, fat tissue, muscle, bone, and pancreas are all part of the endocrine system.
Chemicals known as endocrine disruptors can mimic or interfere with hormone action in the body. These chemicals are found in many everyday products, including some plastic bottles and containers, food-can liners, detergents, toys, cosmetics, and pesticides. Over 800 endocrine-disrupting chemicals have been identified. There is concern that exposure to these chemicals may increase risk for some cancers, cause male and female reproductive system problems, increase obesity and diabetes, cause learning and memory problems, and play a role in various other diseases and dysfunctions.
Although endocrine disruptors can act on the body throughout the lifespan, the period of child development, starting as early as around conception and continuing through adolescence, may be an especially sensitive time. During these windows of susceptibility, endocrine disruptors may interfere with processes that determine how tissues are programmed, which may in turn increase susceptibility to adverse health outcomes across the lifespan and future generations.
What NIEHS is doing
NIEHS funds grants aimed at characterizing how endocrine disruptors influence human health through studies in people and animal models and through cell-based approaches that investigate the biological mechanisms involved in associated health effects. Grantees are developing screening methods to identify and characterize new endocrine disruptors and are working to identify biological markers of endocrine disruptor exposure. Other grantee work involves translating research findings into statistical computer models that can provide a picture of the amount of exposure required for adverse health effects.
Knowledge gained through this research area may help in the development of prevention and intervention strategies that reduce the adverse effects of endocrine disruptors.
NIEHS funds grants that are studying the following types of endocrine disruptors (as examples):
- Bisphenol A (BPA): a chemical frequently used in plastics and epoxy resins. NIEHS' Bisphenol A (BPA) Research Program is funding a variety of grants to investigate the health effects of BPA in human studies and animal model systems.
- Dioxins: byproducts of some manufacturing and incineration processes.
- Organophosphates and organochlorines: compounds used in many insecticides, herbicides, and nerve gases.
- Polychlorinated biphenyls (PCBs): chemicals used in electrical equipment. They persist in the environment even though they were banned over 30 years ago.
- Dichlorodiphenyltrichloroethane (DDT): a pesticide banned in 1972 that is still found in the environment today.
- Phthalates: plasticizers used in plastics and in some fragrances and personal-care products.
- Tributyltin and tin compounds: fungicides.
- Perfluorinated Chemicals (PFOA, PFOS): chemicals used in water and stain resistant products.
- Polybrominated and other flame retardants: chemicals used in furniture and many consumer products to protect against burning.
NIEHS also funds grants examining the endocrine effects of air pollution, heavy metals, and solvents. The Institute is interested in expanding the list of chemicals with endocrine disruptor activity under study and funding research examining new endpoints, such as muscle, circadian rhythm, liver, bone, and the gastrointestinal tract. NIEHS would also like to support work aimed at identifying diseases and dysfunctions that were not previously known to be linked with endocrine disruptors; understanding the active sites, pathways, and mechanisms for these chemicals; and developing biomarkers of exposure and effects.
Many EDC studies are examining early life exposures. This field overlaps with studies on developmental origins of health and disease, environmental epigenetics, preconception exposures, transgenerational inheritance, and other windows of susceptibility.
For additional information on what NIEHS grantees are doing, visit our Who We Fund tool.