Too Much Testosterone Kills Brain Cells

WASHINGTON (Reuters) -- Too much testosterone can kill brain cells, researchers say, in a finding that may help explain why steroid abuse can cause behavior changes such as 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.

Apoptosis is the body's way of killing off cells that are unnecessary or die as a natural part of growth. It is programmed cell death. An example of this is the webbing between people's fingers. As an embryo, humans have pronounced webbing between fingers and toes. The cells in the webbed tissue are normally killed off by apoptosis; if not, people are born with webbed digits.

Nerves are like this too--they're highly sensitive to signals that tell them it's time to die. Even though we're born with trillions of brain cells and nerves throughout the body, they normally die as part of their life cycle. The stuff that isn't used is like excess baggage that needs to be eliminated. The rule for the brain and for nerves (and for muscle, and for bone...) is "use it or lose it."

Apoptosis, it turns out, is triggered by high levels of testosterone. This may be analogous to the rapid bodily changes that occur during puberty in males, accompanied by a surge of testosterone.

"Anabolic steroids, which are synthetic versions of the primary male sex hormone testosterone, can be injected, taken orally, or used transdermally. These drugs are Controlled Substances that can be prescribed to treat conditions such as body wasting in patients with AIDS, and other diseases that occur when the body produces abnormally low amounts of testosterone. However, the doses prescribed to treat these medical conditions are 10 to 100 times lower than the doses that are abused for performance enhancement." link