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.
WHY HORMONES IN OUR BODY?
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
(www.herplace.com/hormone-infor/gender-benders.htm)
(http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/SexHormones.html)
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)
THE BOTTOM LINE
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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