Endocrine disruptor
From Biocrawler, the free encyclopedia.
Endocrine disruptors are substances which interfere with the endocrine system by mimicking, blocking or otherwise disrupting the function of hormones.
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The Endocrine System
Endocrine systems are found in most varieties of animal life. The endocrine system is made up of glands, which secrete hormones, and receptor cells which detect and react to the hormones.
Hormones are released by glands and travel throughout the body, acting as chemical messengers. Hormones interface with cells that contain matching receptors in or on their surfaces. The hormone binds with the receptor, much like a key would fit into a lock.
Endocrine Disruptors
Disruption of the endocrine system can occur in various ways. Some chemicals mimic a natural hormone, fooling the body into over-responding to the stimulus, or responding at inappropriate times. Other endocrine disruptors block the effects of a hormone from certain receptors by blocking the receptor site on a cell. Still others directly stimulate or inhibit the endocrine system and cause overproduction or underproduction of hormones. Certain drugs are used to intentionally cause some of these effects, such as birth control pills. These substances are also known as Endocrine Disrupting Chemicals (EDCs) or Hormone Disrupting Chemicals.
Some of the most well-known examples of EDCs are Dioxins, PCBs, PAHs, furans, phenols and several pesticides (most prominent DDT and its derivatives). There is a long list of substances which may disrupt the endocrine system but have not yet been scientifically proved to do so.
In recent years, some scientists have proposed that chemicals might inadvertently be disrupting the endocrine system of humans and wildlife. A variety of chemicals have been found to disrupt the endocrine systems of animals in laboratory studies, and there is strong evidence that chemical exposure has been associated with adverse developmental and reproductive effects on fish and wildlife in particular locations. The relationship of human diseases of the endocrine system and exposure to environmental contaminants, however, is poorly understood and scientifically controversial (Kavlock et al., 1996, EPA, 1997).
One example of the devastating consequences of the exposure of developing animals, including humans, to endocrine disruptors is the case of the potent drug diethylstilbestrol (DES), a synthetic estrogen. Prior to its ban in the early 1970s, doctors mistakenly prescribed DES to as many as five million pregnant women to block spontaneous abortion and promote fetal growth. It was discovered after the children went through puberty that DES affected the development of the reproductive system and caused vaginal cancer.
Since then, Congress has improved the evaluation and regulation process of drugs and other chemicals. The recent establishment of an endocrine disruptor screening program is seen as a significant step.
See Also
External links
- The EU strategy on EDCs (http://europa.eu.int/comm/environment/endocrine/index_en.htm)
- The US EPA (strategy) on EDCs (http://www.epa.gov/scipoly/oscpendo/index.htm)
