Too much testosterone kills brain cells

[belgareth]

Too much testosterone kills brain cells By Maggie Fox, Health and Science

Correspondent
Wed Sep 27, 8:23 AM

ET

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 suicidal tendencies.


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 illness.
"Our

results suggest that the responses to elevated testosterone can be compared with these pathophysiological

conditions," the researchers wrote.

[bronzie]

I was very much into

bodybuilding, and I never used steroids, I have my health intact, thankgod, I cant say that about my bodybuilder

friends....a few years of vanity, and now when they hit 30+ they pay the price with all sorts of ailments and health

issues. this article makes sense...

[Icehawk]

The study itself seems flawed.

Apperantly they injected testosterone into a dish of brain cells and studied the results.
So according to the

findings if men produce 20x more test than women they're 20x stupider?
Also ignored is the 50+ years of

steroidical studies on brain activity. All in all seems to be more of a PR move to get kids off the stuff.

[belgareth]

The results said a certain

amount of testosterone is good but excess isn't. There's no way you can come to the conclussion that men are 20X

stupider because they produce 20X more testosterone. That isn't what the article said. I'm not a medical person

and am not qualified to make value judments on medical tests that I can't even see how they were conducted. I'd

like a lot more information before jumping to any conclussions about these results.

[Icehawk]

The sudy

itself.

Elevated testosterone induces apoptosis in neuronal cells.

* Estrada M,
* Varshney

A,
* Ehrlich BE.

Department of Pharmacology and Cellular and Molecular Physiology, Yale University, New

Haven, Connecticut 06520, USA.iestrada@med.uchile.cl

Testosterone plays a crucial role in

neuronal function, but elevated concentrations can have deleterious effects. Here we show that supraphysiological

levels of testosterone (micromolar range) initiate the apoptotic cascade. We used three criteria, annexin V

labeling, caspase activity, and DNA fragmentation, to determine that apoptotic pathways were activated by

testosterone. Micromolar, but not nanomolar, testosterone concentrations increased the response in all three assays

of apoptosis. In addition, testosterone induced different concentration-dependent Ca2+ signaling patterns: at low

concentrations of testosterone (100 nm), Ca2+ oscillations were produced, whereas high concentrations (1-10 microm)

induced a sustained Ca2+ increase. Elevated testosterone concentrations increase cell death, and this effect was

abolished in the presence of either inhibitors of caspases or the inositol 1,4,5-trisphosphate receptor

(InsP3R)-mediated Ca2+ release. Knockdown of InsP3R type 1 with specific small interfering RNA also abolished the

testosterone-induced cell death and the prolonged Ca2+ signals. In contrast, knockdown of InsP3R type 3 modified

neither the apoptotic response nor the Ca2+ signals. These results support our hypothesis that elevated testosterone

alters InsP3R type 1-mediated intracellular Ca2+ signaling and that the prolonged Ca2+ signals lead to apoptotic

cell death. These effects of testosterone on neurons will have long term effects on brain function.

All

though it does directly argue with tons of research on the effects of supraphysiological levels of testosterone on

the brain. every other one says it IMPROVES cognitive function.

Curvelinear correlations between total

testosterone levels and fluid intelligence in men and women.

1: Int J Neurosci. 1998

Jul;95(1-2):77-83.

* Tan U,
* Tan M.

Department of Physiology, Medical Faculty, Ataturk University,

Erzurum, Turkey. unertan@superonline.com

The relationship between serum total testosterone (T)

level and fluid intelligence (Cattell's Culture Fair Intelligence Test) was studied in young men and women. There

was no significant difference between IQs of men and women. IQ tended to increase with T in men, except at very high

T levels. It was concluded that (i) T may be associated with IQ, even in samples with no sex-related IQ difference;

(ii) too low or too high T may be disadvantageous for fluid intelligence in women; (iii) T may be advantageous for

this kind of IQ in men, except very high T levels.

PMID: 9845018 [PubMed - indexed for MEDLINE]