RE: thyroid disease article

[carol marcus <csmarcus@ucla.edu>]

At 04:32 PM 11/27/00 -0600, you wrote:
>The long version of this article tells how perchlorate is used to treat
>hyperthyroidism.
>
>Regards,
>Susan
>
>VOLUNTEERS TO INGEST POLLUTANT FOR DRINKING WATER STUDY
>from The Los Angeles Times
>
>Every morning for six months, 100 volunteers in San Bernardino are
>dutifully swallowing pills.
>
>But these human volunteers--recruited by Loma Linda University Medical
>Center and paid $1,000 apiece--are not testing a new medication. The
>pills contain an industrial pollutant called perchlorate, a chemical
>found in rocket fuel.
>
>The experiment, which is funded by aerospace giant Lockheed Martin, is
>designed to see whether perchlorate pollution is harmful to human
>health. The intent is to develop data that could influence the setting
>of national and state drinking-water standards.
>
>The unusual research raises ethical questions about whether scientists
>should allow volunteers to ingest chemicals or pesticides in the quest
>to understand the dangers of environmental contaminants. Several small,
>industry-funded experiments on human volunteers have been conducted in
>recent years for some compounds, like perchlorate, where the risks of
>consuming low levels are poorly understood.
><http://www.latimes.com/news/science/science/20001127/t000113773.html>
>-- 
>.....................................................
>Susan L. Gawarecki, Ph.D., Executive Director
>Oak Ridge Reservation Local Oversight Committee
>                       -----                       
>The LOC newsletter "Insights" is posted on our Web site
>http://www.local-oversight.org - E-mail loc@icx.net 
>.....................................................
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Dear Radsafers:

Perchlorate is used in a diagnostic test to diagnose organification defects
in thyroid glands, and has been used for this for probably 30+ years.  It is
called the "Perchlorate Discharge Test". Perchlorate is also commonly used
to block pertechnetate uptake in a variety of nuclear medicine diagnostic
tests in which uptake of oxidized technetium-99m (pertechnetate) can confuse
a diagnostic study. In vivo oxidation of Tc-99m in various
radiopharmaceuticals is inevitable, and so perchlorate is kept around in
many Nuclear Medicine Depts. to enhance the validity of a variety of
diagnostic tests using Tc-99m radiopharmaceuticals. 

Perchlorate is a monovalent anion, and is transiently taken up in thyroid
glands like iodide, another monovalent anion.  Whereas iodide is attached to
an organic molecule to make thyroid hormone, perchlorate is not, and soon
washes out of thyroid cells. 

Both sodium and potassium perchlorate are in the USP, and a potassium
perchlorate capsule is an FDA-approved drug.  

Perchlorate is not the standard of medical practice for treating
hyperthyroidism.

I have considerable doubts that trace quantities of perchlorate in drinking
water will have any adverse effects on the thyroid or any other organ.
However, I don't know what levels occur in drinking water. 

Ciao, Carol

Carol S. Marcus, Ph.D., M.D.
<csmarcus@ucla.edu>    

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