快猫短视频

ATHLETES who protest their innocence after testing positive for the banned steroid nandrolone could have a fresh chance to clear their names. A new test distinguishes between manufactured nandrolone and that produced naturally in the body.

Some athletes undoubtedly take nandrolone, which helps build muscle. But the frequency at which athletes fail tests for the substance has raised doubts about their accuracy (快猫短视频, 14 August 1999, p 4). In 1999, British sprinter Linford Christie tested positive for nandrolone and the Dutch footballer Jaap Stam served a ban after failing a test last year.

In the body, nandrolone breaks down to produce 19-norandrosterone (19-NA), the compound nandrolone tests look for. But this substance also occurs naturally as a by-product of oestrogen production. The International Olympic Committee (IOC) sets a maximum limit for 19-NA in urine of 2 nanograms per millilitre for men and 5 nanograms per millilitre for women, who produce more 19-NA.

But according to Bruno Le Bizec at the National Veterinary School of Nantes in France, natural levels of 19-NA can get close to the IOC limits, and if tests are not precise, innocent people could test positive. Between 1998 and 2000, Le Bizec tested 385 urine samples from 40 French football players and coaches. The natural level of 19-NA was up to 1.8 nanograms per millilitre.

To see if 19-NA that occurs naturally differs from 19-NA resulting from nandrolone abuse, Le Bizec and his team recruited six volunteers to take nandrolone mixed into water. Le Bizec found that in people who have taken nandrolone supplements, around 30 per cent of the 19-NA was bound chemically to a sulphate. Conversely, all the natural 19-NA was bound to a derivative of glucose called glucuronic acid.

Le Bizec says this test would be useful for double-checking a positive result when an athlete has failed by a small margin. He has called on the IOC to look into it. 鈥淚 think they should apply what we鈥檝e found to the urine samples they keep from positive tests to see if they still test positive,鈥� he says.

John Honour, an endocrinologist at University College Hospital in London, who took part in a review of nandrolone abuse for Britain鈥檚 national sports council, says Le Bizec faces an uphill struggle. 鈥淒ope-testing labs will be unlikely to adopt the test voluntarily because it will add to their costs,鈥� he says.

But Patrick Schamasch, medical director of the IOC in Lausanne, Switzerland, is keeping an open mind: 鈥淲e have good tests already, but if this could show more clearly what鈥檚 going on, it would be valuable.鈥�