Improved doping test for growth hormone on its way

Anti-doping agents may soon get a better shot at catching athletes who inject growth hormone to bulk up and enhance performance.

Agents currently have only 24 hours after the prohibited substance is injected before their lab tests can no longer trace it. But a long-awaited experimental test that works for at least two weeks after drug use just cleared an important scientific hurdle.

On Wednesday, British doctors reported that the new detection method is reliable even in junior athletes, whose naturally high levels of growth hormone in principle might have triggered a false alarm.

"Despite the fact that there are differences in hormone levels in young athletes, none of them was falsely accused," said Dr. Richard Holt of the University of Southampton, U.K., who tested the new method on British elite athletes aged 12 to 20 years.

"Our hope is that if you have an effective test, that will dissuade athletes from taking growth hormone," added Holt. The findings were published in the Journal of Clinical Endocrinology & Metabolism.

Human growth hormone is naturally produced in the brain's pituitary gland. It stimulates bone and muscle growth, which has put it on the World Anti-Doping Agency's (WADA) List of Prohibited Substances and Methods.

Tests for the hormone were only introduced in 2004, according to WADA's website. And this past February, British rugby player Terry Newton became what the agency called "the first completed case involving an analytical finding for human growth hormone." He accepted a two-year sanction without contest.

The new method works by detecting two proteins - called IGF-I and P-III-P - that are present in the blood and reflect growth hormone levels. Known as GH-2000, it was originally slated to be introduced at the 2000 Summer Olympics in Sydney. But scientific concerns about its reliability in different ethnic groups and age groups held it back.

At this point, said Holt, it has cleared all except one hurdle, and his team expects to complete the pre-market tests by the end of 2010.

Holt and WADA, which funded part of the GH-2000's development, do not want to reveal the exact date the new detection method will be introduced. They prefer it to make it a surprise to any athlete who might be cheating.

"We strongly suspect that a number of elite athletes are abusing growth hormone as a means of improving their performance," Holt said

SOURCE: Journal of Clinical Endocrinology & Metabolism, online April 21, 2010.