From the archive, originally posted by: [ mmm ]
Too much testosterone kills brain cells
By Maggie Fox / Sep 27, 2006
WASHINGTON (Reuters) – Too much testosterone can kill brain cells,
researchers said on Tuesday in a finding that may help explain why
steroid abuse can cause behavior changes like aggressiveness and
Tests on brain cells in lab dishes showed that while a little of the
male hormone is good, too much of it causes cells to self-destruct in
a process similar to that seen in brain illnesses such as Alzheimer’s.
“Too little testosterone is bad, too much is bad but the right amount
is perfect,” said Barbara Ehrlich of Yale University in Connecticut,
who led the study.
Testosterone is key to the development, differentiation and growth of
cells and is produced by both men and women, although men produce
about 20 times more of the hormone.
It can also be abused, and recent scandals have involved athletes who
use the hormone, or steroids that turn into testosterone in the body,
for an unfair advantage.
“Other people have shown that high levels of steroid can cause
behavioral changes,” Ehrlich said in a telephone interview.
“We can show that when you have high levels of steroids, you have high
testosterone and that can destroy the nerve cells. We know that when
you lose brain cells you lose function.”
Ehrlich’s team tried the same thing with the “female” hormone
estrogen, just to be fair.
“We were surprised, but it actually looks like estrogen is
neuroprotective. If anything, there is less cell death in the presence
of estrogen,” she said.
Writing in the Journal of Biological Chemistry, Ehrlich and colleagues
said their findings meant people should think twice about
supplementing with testosterone, even if it does build muscle mass and
aid recovery after exercise.
“These effects of testosterone on neurons will have long term effects
on brain function,” they wrote.
“Next time a muscle-bound guy in a sports car cuts you off on the
highway, don’t get mad — just take a deep breath and realize that it
might not be his fault,” Ehrlich said in a statement.
The cells die via a process called apoptosis, also known as cell
suicide or programmed cell death.
“Apoptosis is an important thing for the brain — the brain needs to
weed out some of the cells. But when it happens too frequently, you
lose too many cells and causes problems.”
A similar process is seen in Alzheimer’s disease, the most common
cause of dementia in the United States, affecting an estimated 4.5
million Americans, and Huntington’s disease, another fatal brain
“Our results suggest that the responses to elevated testosterone can
be compared with these pathophysiological conditions,” the researchers