[extropy-chat] Thyroxine

[Dirk Bruere]

http://news.bbc.co.uk/1/hi/health/4396495.stm

Pill 'could lead to longer lives'
* People could one day extend their lifespan by up to 30 years by taking 
a pill, a scientist has claimed. *

Professor John Speakman, from Aberdeen University said the hormone 
thyroxine could boost metabolism and so lifespan.

He said tests on mice suggested, if the right dose could be identified, 
humans who would otherwise have died aged 70 could live to 100.

But a leading hormone specialist warned too much thyroxine can cause 
potentially fatal health problems.


	* Mice have a different metabolism to humans *
Dr Pierre Bouloux, Royal Free Hospital

Studies carried out by the Aberdeen University team showed the mice with 
the highest metabolic rate lived around 25% longer than those with the 
lowest.

Professor Speakman said this would translate to a difference of around 
30 years in humans.

When mice were given thyroxine, they had increased metabolic rates and 
lived longer, compared with animals who were not given the hormone.

Thyroxine is already given to people who do not produce enough of the 
hormone naturally, so that they have a healthy metabolic rate.

But people with too much thyroxine in their bodies also have to take 
medication to bring their level back to normal.

* 'Longer lives' *

Thyroxine boosts the body's metabolic rate which has a beneficial effect 
on cell biology, setting off a process which reduces the production of 
damaging free radicals.

Professor Speakman, who has been awarded a £450,000 grant by the 
Biotechnology and Biological Sciences Council said: "We know thyroxine 
affects your metabolic rate.

"The key is getting the right dose."

He will now carry out research where mice to determine the most 
effective dose of the drug.

Professor Speakman said it might not be possible to find a level which 
did not have detrimental effects on human health.

But he said there were other molecules which could have the same effect 
on uncoupling proteins.

* 'Not true for humans' *

Professor Speakman said: "The end point of this research is the hope 
we'll be able to give people extra healthy years. We don't want to 
extend their stay in a nursing home."

His work is set to be published in the Journal of Experimental Biology.

However, a leading specialist in human hormone disorders said the 
findings would "not be true for humans".

Dr Pierre Bouloux, an endocrinologist at the Royal Free Hospital in 
London said: "This is an example of research being extrapolated on the 
basis that a mouse represents the best model for a man. It doesn't.

"Mice have a different metabolism to humans."

He added: "Having an over-active thyroid gland puts you at a three-fold 
risk of potentially fatal heart disorders and a three to four-fold risk 
of osteoporosis.

"An over-active thyroid causes considerable morbidity in the ageing 
population."

And he warned people who had even a slightly higher level of thyroxine 
were at risk of ill health.


-- 
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org



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