What Are Endocrine Disruptors?

By Katy Califf

Endocrine disruptors are chemical compounds in the environment that interact with hormone receptors in an organism’s body, either inhibiting or mimicking hormone activities. Hormones are biochemicals that are produced by endocrine glands and travel through the blood stream. Examples of endocrine glands are the pituitary, thyroid, adrenal glands, ovaries, and testes. Hormones are secreted by these glands and elicit responses from other parts of the body. These chemicals can affect young before the birth through the womb, and can have disastrous effects during this critical development period.

Some endocrine disruptors have been found to accumulate in the fatty tissue of animals and can build up to extreme levels. These concentrations multiply moving up the food chain. Animals at the top of the food chain can have concentrations that are multiplied 25 million times.

Endocrine disruptors come from a variety of sources. Chemical and industrial waste, pesticides, pharmaceuticals, oral contraceptives, detergents, food additives, and plastics are all sources of environmental toxins and endocrine disruptors. These chemicals spread far and wide. Even polar bears in the high arctic, far from any humans, have PCBs and other toxins in their bodies.

The first endocrine disruptors identified were those that acted as estrogen mimics, binding to estrogen receptors and “fooling” the body into over-responding or responding at the wrong time. There are naturally occurring “phytoestrogens” found in plants that have these same effects, but for our purposes, endocrine disruptors are considered man-made chemicals only. The reason these man-made chemicals can have such disastrous effects while naturally occurring plant estrogens do not is because organisms are suddenly faced with these man-made chemicals and have never encountered them before. They have not evolved mechanisms to cope with these chemicals and are therefore unprepared to respond to them.

Today hundreds of the existing thousands of endocrine disruptors have been identified. Many of them, such as DDT (dichloro-diphenyl-trichloroethane) and PCBs (polychlorinated-biphenyls) have been banned or are under severe governmental regulations in some countries, but their use persists in developing countries.