Posted on 03/31/2008 12:38:19 AM PDT by neverdem
A genetic quirk could help cheating athletes beat drug tests and could unfairly taint fair players.
The genetic variation affects an enzyme that processes testosterone. Testosterone is naturally made in the body by both men and women, although it is primarily known as a male sex hormone. In order to distinguish between naturally present hormone and synthetic testosterone from steroid use, drug tests measure a ratio of two chemicals found in urine.
One chemical, epitestosterone glucuronide (EG), is made at a constant level in the body, regardless of testosterone levels. The other chemical, testosterone glucuronide (TG), is a testosterone by-product.
Testers measure the ratio of TG to EG. Any amount of TG greater than four times the level of EG is considered a red flag for doping.
An enzyme called UGT2B17 adds a chemical to testosterone to prepare it for secretion in the urine. A group of scientists in Sweden found that some people completely lack the gene that produces UGT2B17, and this difference could affect results of doping tests.
About 15 percent of 145 healthy male volunteers lacked the enzyme entirely. Just over half the volunteers (52 percent) had one copy of the gene, and one-third of the men had two copies.
Some of the men were selected to get a single shot of testosterone. The researchers monitored production of TG in the men's urine for 15 days after the injection.
About 40 percent of the people who lacked the enzyme never secreted enough TG to raise warning flags in the standard test, even after getting a hormone shot, the team reports online in the Journal of Clinical Endocrinology & Metabolism.
"There is a risk that many such individuals have escaped detection," says Anders Rane of the Karolinska Institute in Stockholm, Sweden, and one of the authors of the...
(Excerpt) Read more at sciencenews.org ...
I think it was elevated testostorne that got Floyd Landis stripped of his 2006 Tour De France win.
Wonder if this is related at all. The guy’s claimed his innoncence throughout. Then again, that doesn’t always mean anything...
I wish it meant more...
Someone should tell Landis to determine whether he’s in that subset that could test false positive.....
Looks like genetic testing will have to be used with the piss test. So much for keeping it simple.
The TdF has picked teams for this years race and the winner of the 2006 race has not yet been determined.
And two of the three podium finishers from last year? Their new team, Astana, was not invited to this years race.
European Bike racing - better than American Soaps any day.
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