Tuesday, May 13, 2014



Written by: Kashobwe Lackson

What are hormones?

 Hormones are chemical messages that are released from the body’s gland tissues located in the endocrine system. The chemical information is sent as a signal through the blood stream to the targeted cells that contain receptors.  The function of hormones on the targeted cells is to deliver the chemical message that activates the cell to perform a specific task, for example, estrogen from the endocrine system is responsible for egg (ovum) release during ovulation. An illustration of hormone release from the secreting cells and its flow to a targeted cell is shown below (image from: www.sinauer.com) in fig 1.

Fig 1. Flow of the hormone to targeted organ


When hormones are released into the blood stream they bind to a cell containing matching receptors; their shape is like a key that fits exactly into a lock. Just as the wrong key cannot open the door, hormones do not fit in cells that have no receptors. Hormones reach all parts of the body and only attach to a cell containing receptors in order to produce a particular effect. If there is no attachment to the cell’s receptors, no effect will be produced. When a hormone binds to the cell it either changes the cell’s existing protein or activates genes responsible for new protein synthesis. According to researchers 50 hormones have been identified in humans and other vertebrates.


Hormones in the human body are secreted by the endocrine system and released into the bloodstream to all parts of the body; they regulate the biological activities such as reproduction and growth. For example, hormones regulate the reproductive system starting from conception (the process where female egg and male sperm fuse together) and continue to regulate the growth and function of the reproductive organs into adulthood. Hormones also regulate the development of the brain and nervous system.  For more… (http://www.epa.gov/endo/pubs/edspoverview/whatare.htm)
The focus of this blog is reproductive hormones that are secreted by ovaries and testes.

What are reproductive Hormones?

Reproductive hormones are secreted from ovaries and testes and are sent to all parts of the body via the blood stream. Ovaries are female reproductive organs and produce two main hormones known as estrogen and progesterone. Testes are the male reproductive organs, and they function to release a hormone called testosterone. The function of both female and male hormones is to regulate and enhance the development of reproductive organs, and for example, breast growth in females and chest enlargement in males as well as ovum (egg) and sperm synthesis.

Hormone inhibitors and their mimicking effects

Hormone inhibitors, colloquially known as gender benders, are any chemicals capable of inhibiting or preventing the effect of hormones, as well as mimicking a hormone’s action. The mimicking effect happens as the result of environmental chemicals having a similar chemical structure to natural hormone; this allows them to weakly attach to the cell’s receptors, thereby preventing the attachment of natural hormones to the same cell. These chemicals include Persistent Organic Pollutants (POPs) such as DDT, Dioxin, PCB and Endrin, Aldrin and Dieldrin.  POP chemicals are present in the environment because some of them are used in industrial applications; these include PCB, Dieldrin and Dioxins.  Others, such as DDT, have been widely used as pesticides.  (DDT is now banned in many countries, but its effects persist.)  Others get into the environment as waste products of human activities such as nuclear power generation, burning of coal, mining, waste incineration (burning of waste), and manufacturing of some plastics that are made of PCB chemical compounds.

 Several studies conducted by scientists indicate that human exposure to POPs is through air pollution and water contamination, because most of these chemicals are released into lakes or rivers, and air.  A study carried out by Elizabeth Lee Vliet MD, in 2003 indicated that there is a link between these environmental chemicals and reproductive hormones. Natural hormones such as estrogen and testosterone are blocked from attaching to their receptors because the environmental chemicals such as DDT, Dioxin and PCB, when they enter the bloodstream, attach to cell receptors intended for natural hormones. Thus estrogen and testosterone hormone are prevented from attaching to the same cell, resulting in health risks. See more at          

Effects of Hormone inhibitors

Hormone inhibitors in the human body may cause the body to react abnormally. For example, the reaction could be abnormal sperm synthesis in males and disruption of the menstruation cycle, miscarriages, premature delivery, low birth weight and dysfunction in fetus and infants in women. Other areas include neurological disorders such as learning disorders and distorted memory as well as, diseases like breast and pancreatic cancer, and soft tissue sarcoma (tissue hardening)


Thus, there is a need to focus on how hormone inhibitors can be removed from the environment, and vigorously promote the production of safe alternative chemicals that are environmentally friendly


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