Hormone Disruptors

(also known as 'endocrine disruptors'):

[Toxins that affect the endocrine system]

Hormone disrupting chemicals are structurally similar to natural hormones, and trick the body by either mimicking or blocking normal hormonal functions (Toxic Nation Canada, 2006).

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 (e.g., a growth hormone that results in increased muscle mass), or responding at inappropriate times (e.g., producing insulin when it is not needed). Other endocrine disrupting chemicals block the effects of a hormone from certain receptors (e.g. growth hormones required for normal development). Still others directly stimulate or inhibit the endocrine system and cause overproduction or underproduction of hormones (e.g. an over or underactive thyroid). Certain drugs are used to intentionally cause some of these effects, such as birth control pills. In many situations involving environmental chemicals, however, an endocrine effect is not desirable (EPA 2011). 

They affect the body's hormone-producing glands:

• The pituitary gland and hypothalamus located in the brain, 
• The adrenal glands on top of the kidneys, 
• The female ovaries and male testicles, 
• The pancreas in the abdomen, and 
• The parathyroid and thyroid glands in the neck.

Hormones that are released from glands act as messengers that evoke a specific response in other cells throughout the body.

These hormones regulate almost every cell, organ, and function of our bodies, including:

• Reproduction, 
• Metabolism, 
• Regulation of nutrients and minerals, 
• Body temperature, 
• Moods, 
• The immune system, 
• Growth and development.

Health effects:

• Adverse pregnancy outcomes (still births, changes in sex ratio, i.e. fewer male babies), male birth defects (undescended testes and hypospadius), 
• Decreased sperm count and quality, 
• Early onset of menstruation and puberty, 
• Neurobehavioural effects (resulting from altered thyroid hormone function in utero), 
• Endocrinemediated immunotoxicity, and 
• Cancer promotion at endocrine sites (breast, endometrial, testes, prostate, and thyroid).

Examples of chemicals suspected or known to disrupt hormones:

• Heavy metals, 
• PCBs, 
• Organochlorine pesticides, 
• Dioxins and furans, 
• Phthalates, 
• Bisphenol A (AKA:  BPA), and 
• PBDEs.

*This info is mostly taken directly from Polluted Children, Toxic Nation:  A Report on Pollution in Canadian Families , pages 11-14 (that is the page on the actual document, and not the page of the PDF, which also numbers the title pages).