Humans and other animals (fish, birds, reptiles, amphibians, and
mammals) all have three great internal networks that coordinate growth,
development, and behavior:
** the nervous system (brain, spinal cord, and peripheral nerves);
** the immune system (a myriad of specialized cells and tissues that
protect us against bacteria, viruses, and cancers); and
** the endocrine system, which controls and coordinates the body by
sending chemical messages (hormones) through the blood stream, turning
on and off various functions throughout the body.
The human body is more than a mere collection of 50 trillion individual
cells because our cells work together. Working together requires
coordination, which requires communication.
Nerves are just one avenue of communication--the one employed for
rapid, discrete messages, such as a quick instruction to a hand, to
move away from a hot stove. A large part of the body's internal
communication and control is carried out via the bloodstream, where
hormones and other chemical messengers move about, carrying signals
that not only govern sex and reproduction but also coordinate organs
and tissues that work together to keep the body functioning properly.
Hormones --chemical messengers --began to be understood early in this
century. Nobel prizes were awarded for the discovery of insulin in
1923, and for work on sex hormones in 1939. The best-known hormones are
estrogen (the main female sex hormone) and testosterone (the main male
sex hormone) but by 1987 more than 100 hormones had been identified in
humans and higher mammals.
The endocrine (hormone) system plays an important role starting early
in life's beginnings. It is the endocrine system that controls
development of the embryo. The embryo begins as a single fertilized egg
cell, which divides again and again, creating new cells; these cells in
turn "differentiate" into different kinds of cells, thus creating a
brain, eyes, fingers, genitalia, and so forth. All of these processes
are controlled by hormones.
In 1950, researchers at Syracuse University exposed young roosters to
DDT and showed that their testicles only grew to 18 percent of normal
size. The researchers concluded, "These findings suggest that DDT
may exert an estrogen-like action..."
A 1963 study in the JOURNAL OF THE NATIONAL CANCER INSTITUTE showed
that cysts and cancers developed in mice treated with estrogen as
newborns. In that 1963 study, author Thelma Dunn warned that her work
showed "the vulnerability of the immature animal to the harmful effects
of exposure to a naturally occurring hormone."
The following year, in 1964, two authors writing in the JOURNAL OF THE
NATIONAL CANCER INSTITUTE reported changes in vaginal tissues in mice
after exposure to estrogen shortly after birth. They warned, "We feel
that abnormal hormonal environments during early postnatal (and
antenatal) life should not be underestimated as to their possible
contribution to abnormal changes of neoplastic [cancer] significance
later in life."
These early warnings were ignored. From about 1940 onward, roughly 1000
new chemicals were introduced into commercial channels each year (a
practice that continues today). No one asked whether any of these
chemicals might exert an estrogen-like effect or might in some other
way disrupt the chemical-messaging system on which we all depend for
health and well-being. Still today, no one in any official capacity is
Starting in the 1950s, papers began to appear in scientific journals
showing declines in wildlife populations, resulting from exposures to
certain pesticides. Reports of odd behavior began to appear as well --
pairs of female gulls (so-called "gay gulls") sharing nests; pairs of
terns (birds on the Great Lakes) failing to sit on their eggs,
neglecting to defend their nests against predators. Alligators with
penises so small they couldn't reproduce. As time passed, hundreds of
such studies accumulated from many parts of the world.
However, it wasn't until 1991 that some scientists began to see a
pattern in these studies. In July of that year, Theo Colborn, a
biologist with the World Wildlife Fund, invited a group of 20
scientists to discuss their research. To their surprise, the scientists
all agreed that, in their individual research, they were seeing
evidence that industrial chemicals in the environment were harming the
endocrine systems of fish, birds and mammals. They issued a consensus
document, now known as the Wingspread statement (see REHW #263, #264),
which began, "We are certain of the following:
"A large number of man-made chemicals that have been released into the
environment, as well as a few natural ones, have the potential to
disrupt the endocrine system of animals, including humans. Among these
are the persistent, bioaccumulative, organohalogen compounds that
include some pesticides (fungicides, herbicides, and insecticides) and
industrial chemicals, other synthetic products, and some metals." [An
organohalogen is a chemical that contains carbon attached to a halogen
such as chlorine; there are now 15,000 chlorine-containing organic
compounds in commercial use.]
The Wingspread statement went on,
"Many wildlife populations are already affected by these compounds. The
impacts include thyroid dysfunction [impaired or abnormal functioning]
in birds and fish; decreased fertility in birds, fish, shellfish, and
mammals; decreased hatching success in birds, fish and turtles; gross
birth deformities in birds, fish and turtles; metabolic abnormalities
[impaired or abnormal use of energy, manufacture of tissue, or handling
of resulting wastes] in birds, fish, and mammals; behavioral
abnormalities in birds; demasculinization and feminization in male
fish, birds, and mammals; defeminization and masculinization of female
fish and birds; and compromised [impaired] immune systems in birds and
mammals." This was the first time anyone had ever put two and two
together and had concluded that industrial chemicals are interfering
with hormones in wildlife and, by analogy, probably in humans.
Since 1991, the journals have continued to swell with new studies
showing how industrial chemicals, in low concentrations, can disrupt
In some instances, industrial chemicals behave like (mimic) hormones,
fooling the body into responding as if natural hormones are present
when in fact they are not, thus sending fake messages. In other
instances, industrial chemicals block (partially or fully) the action
of natural hormones, thus interfering in the receipt of messages. In
other instances, industrial chemicals block the production of hormones,
thus preventing the sending of messages. In still other instances,
industrial chemicals interfere with the body's normal ability to break
down and eliminate hormones, thus resulting in too many messages being
present simultaneously and for too long.
No matter where you live today --whether in New York City, or on a
remote island in the Arctic Ocean, anyone willing to put up the $2000
for testing will find more than 250 synthetic industrial chemicals in
their body. DDT was first reported in human milk in 1951 and by the
early 1980s, 192 different industrial chemicals (pesticides, solvents,
etc.) were measurable in mothers' milk.
These industrial chemicals are routinely present in our tissues at
levels measured in parts per billion (or, in extreme instances, parts
per million). On the other hand, naturally-occurring hormones often do
their work at levels that are measured in parts per trillion, one
thousand times lower than parts per billion and a million times lower
that parts per million.
Furthermore, there is evidence that industrial chemicals at exceedingly
low levels can combine together to produce additive effects. Dr. Ana
Soto at Tufts University combined 10 hormone disrupters, each at one-
tenth of the dose required to produce a minimal response; she found
that the combination produced a response. Thus combinations of
chemicals must be taken into account when we try to learn how much
"effective exposure" we are getting to hormone-disrupting chemicals.
Is there any evidence that humans have been harmed? Yes, there is. The
medical profession exposed millions of women to drugs called
thalidomide and DES (diethylstilbestrol) before it was learned that
birth defects might result from such exposures. The DES exposures,
particularly, provided compelling evidence that humans respond to
hormone-disrupting chemicals the way other mammals do. Studies of
humans exposed to PCBs (a class of hormone-disrupting industrial
chemicals) shown mental and physical stunting. (See REHW #295, #372.)
(We will review additional human evidence in future issues.)
OUR STOLEN FUTURE, Theo Colborn's new book, presents evidence and
hypotheses pointing toward a variety of effects in humans: reduced
sperm count; increases in cancer of the prostate, testicles, and female
breast; diminished intelligence; reduced capacity to pay attention;
increased aggression and violence. Are these things all proven? They
are not. Are they plausible enough and important enough to warrant
thoughtful preventive action by prudent people? They definitely are.
What lessons can we learn from all this? Many. But they will have to
wait. For the next two weeks, we will focus on the institution that
allowed our future to be stolen --indeed, made it all but certain that
our future would be stolen. Stay tuned.
 Anthony W. Norman and Gerald Litwack, HORMONES (San Diego, Ca.:
Academic Press, 1987), pg. xi. And see Appendix A.
 H. Burlington and V.F. Lindeman, "Effects of DDT on Testes and
Secondary Sex Characters of White Leghorn Cockerels," Proceedings of
the Society for Experimental Biology and Medicine Vol. 74 (1950), pgs.
48-51. Even earlier, the sexual development of mice had been disrupted
by exposure to estrogen: R. Greene and others, "Experimental
Intersexuality: The Paradoxical Effects of Estrogens on the Sexual
Development of the Female Rat," ANATOMICAL RECORD Vol. 74 No. 4 (1939),
pgs. 429-438. And: R. Greene and others, "Experimental Intersexuality:
Modification of Sexual Development of the White Rat With a Synthetic
Estrogen," PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND
MEDICINE Vol. 41 (1939), pgs. 169-170.
 T. Dunn and A. Green, "Cysts of the Epididymis, Cancer of the
Cervix, Granular Cell Myoblastoma, and Other Lesions After Estrogen
Injection in Newborn Mice," JOURNAL OF THE NATIONAL CANCER INSTITUTE
Vol. 31 (1963), pgs. 425-438.
 N. Takasugi and H. Bern, "Tissue Changes in Mice with Persistent
Vaginal Cornification Induced by Early Postnatal Treatment With
Estrogen," JOURNAL OF THE NATIONAL CANCER INSTITUTE Vol. 33 (1964),
 Theo Colborn, Dianne Dumanoski and John Peterson Myers, OUR STOLEN
FUTURE (N.Y.: Dutton, 1996), pgs. 251-260 reprints the Wingspread
 J.S. Stanley, [Midwest Research Institute, Kansas City, Mo.], BROAD
SCAN ANALYSIS OF HUMAN ADIPOSE TISSUE. EXECUTIVE SUMMARY. VOLUME 1.
FINAL REPORT. [EPA/560/5-86/035] (Springfield, Va: National Technical
Information Service [NTIS No. PB 87-177218/REB]. See also VOLUME II,
NTIS No. PB 87-177226. And see: Kristin Bryan and Theo Colborn,
"Organochlorine Endocrine Disruptors in Human Tissue," in Theo Colborn
and Coralie Clement, editors, CHEMICALLY-INDUCED ALTERATIONS IN SEXUAL
AND FUNCTIONAL DEVELOPMENT: THE WILDLIFE/HUMAN CONNECTION [Advances in
Modern Environmental Toxicology Vol. XXI] (Princeton, N.J.: Princeton
Scientific Publishing Co., 1992), pgs. 365-394.
 E.P. Laug and others, "Occurrence of DDT in Human Milk," ARCHIVES
OF INDUSTRIAL HYGIENE Vol. 3 (1951), pgs. 245-246. And see: Edo D.
Pellizzari and others, "Purgeable Organic Compounds in Mother's Milk."
BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY Vol. 28 (1982),
pgs. 322-328, reporting 192 different industrial chemicals in samples
of human milk from New Jersey, Pennsylvania and Louisiana.
 In their Appendix A, Norman and Litwack, cited above in note 1,
list the levels at which naturally-occurring hormones are present in
human blood. Many occur in the low parts per trillion range.
 Soto's work is reported in Paul Cotton, "Environmental Estrogenic
Agents Area of Concern [sic]," JOURNAL OF THE AMERICAN MEDICAL
ASSOCIATION Vol. 271, No. 6 (February 9, 1994), pgs. 414-415.
Descriptor terms: our stolen future; theo colborn; john peterson myers;
dianne dumanoski; nervous system; immune system; endocrine system;
hormones; development; embryo; estrogen; endocrine disrupters;
wingspread statement; pesticides; thyroid disease; infertility;
wildlife; fish; birds; mammals; synergism; additive effects; ana soto;