- Hello Jeff - My question is: what is the effect on humans
who consume such estrogen-fed factory-farmed - and wild - fish?
- What about other pharmaceuticals that are also finding
their way to rivers and into the fish?
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- We need to stop using so many pharmaceuticals. Years
ago you were hard pressed to find people who relied upon medication on
a life-long daily basis. Now it seems that almost everyone is on some
form of pharmaceutical and, in many cases, unnecessarily.
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- Patty
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- US - Estrogen Linked To Lowered Immunity In Fish
- By Laura Robertson
- United States Geological Survey
- 6-3-9
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- Exposure to estrogen reduces production of immune-related
proteins in fish. This suggests that certain compounds, known as endocrine
disruptors, may make fish more susceptible to disease.
- The research may provide new clues for why intersex fish,
fish kills and fish lesions often occur together in the Shenandoah and
Potomac rivers. The tests were conducted in a lab by scientists from the
U.S. Geological Survey.
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- The study, led by USGS genomics researcher Dr. Laura
Robertson, revealed that largemouth bass injected with estrogen produced
lowered levels of hepcidin, an important iron-regulating hormone in mammals
that is also found in fish and amphibians. This is the first published
study demonstrating control of hepcidin by estrogen in any animal.
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- Besides being an important iron-regulating hormone, researchers
also suspect that hepcidin may act as an antimicrobial peptide in mammals,
fish and frogs. Antimicrobial peptides are the first line of defense against
disease-causing bacteria and some fungi and viruses in vertebrate animals.
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- "Our research suggests that estrogen-mimicking compounds
may make fish more susceptible to disease by blocking production of hepcidin
and other immune-related proteins that help protect fish against disease-causing
bacteria," said Robertson.
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- USGS researchers Drs. Vicki Blazer and Luke Iwanowicz
have previously found intersex occurring in fish in the Potomac and Shenandoah
rivers. Intersex is primarily revealed in male fish that have immature
female egg cells in their testes. Because other studies have shown that
estrogen and estrogen-mimicking compounds can cause intersex, the co-occurrence
of fish lesions, fish kills and intersex in these two rivers suggested
to USGS scientists that estrogen-mimicking compounds could be involved
in the fish lesions and fish kills in addition to being a possible cause
of intersex traits.
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- That caused Robertson and her colleagues to investigate
how estrogen could be affecting the immune system in these fish. The study
showed that largemouth bass produced two different hepcidin proteins. Production
of the first hepcidin protein was "turned down" by estrogen.
Production of the second hepcidin protein by fish exposed to bacteria was
blocked by estrogen. The fact that estrogen blocked production of hepcidins
in fish exposed to bacteria gives more weight to the theory that estrogen
or estrogen-mimicking chemicals could be making fish more susceptible to
diseases, Robertson added.
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- Hepcidin could protect against bacterial infection in
two ways. "First," said Robertson, "hepcidin could be an
antimicrobial peptide that actually kills pathogens. Or it could be more
complex. To live, a microbe must have iron, so when a microbe invades a
person or animal, that microbe must obtain iron from its host. To 'fight'
the microbe, a host can 'suck up iron' and store it in places inaccessible
to the microbe. In mammals, hepcidin is a key player in how the host takes
up and stores iron."
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- The study, Identification of centrarchid hepcidins and
evidence that 17É¿-estradiol disrupts constitutive expression
of hepcidin-1 and inducible expression of hepcidin-2 in largemouth bass
(Micropterus salmoides), was just published in the journal, Fish &
Shellfish Immunology. The authors are USGS scientists Laura Robertson,
Luke Iwanowicz and Jamie Marie Marranca.
- USGS provides science for a changing world. For more
information visit www.usgs.gov.
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- Subscribe to USGS News Releases via our electronic mailing
list or RSS feed.
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- http://www.eurekalert.org/pub_releases/2009-06/usgs-elt060309.php
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- Patricia A. Doyle DVM, PhD Bus Admin, Tropical Agricultural
Economics Univ of West Indies Please visit my "Emerging Diseases"
message board at:
- http://www.emergingdisease.org/phpbb/index.php Also my
new website:
- http://drpdoyle.tripod.com/ Zhan le Devlesa tai sastimasa
Go with God and in Good Health
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