UK researchers are working to develop a new drug test to detect growth hormone abuse in time for the 2004 Athens Olympics.
The test could be used at the Athens Olympics
Growth hormone abuse is a growing problem in sport, but it can be hard to spot because the substance occurs naturally in the body.
The hormone prompts the body to turn food into muscle rather than fat. It is usually used during training, but it is banned by the International Olympic Committee (IOC).
A team from Southampton University is developing a test which can detect levels of proteins produced by the hormone.
Early findings show abusers have five times the levels of the proteins compared to what would normally be expected.
The levels of proteins are huge in comparison to the levels people produce themselves
Dr Cathy McHugh, Southampton University
The scientists have received over $1,229,000 from the US Anti-Doping Agency and the World Anti-Doping Agency to develop the test.
Growth hormone is naturally produced by the pituitary gland in short bursts. Exercise and stress are powerful stimuli for the secretion of the hormone.
If someone takes growth hormone, it can only be detected during the following 24 hours.
But it makes the liver produce two proteins; IGF1 and procollagen 3. These have been shown to be detectable up to 84 days after someone has taken the hormone.
Levels can be up to five times those of someone with a normal amount of growth hormone in their body.
An earlier study looked at mainly Caucasian sportsmen so the IOC has asked the researchers to test other ethnic groups to ensure the test is completely reliable.
The new study will check blood samples from 300 athletes of differing ethnic groups immediately after they have competed to check growth hormone levels.
Sixty will be followed up over a year. Another 50 athletes will be studied following a sporting injury to see if hormone levels change during their recovery period.
In addition, 90 non-competing volunteers will be treated with growth hormone for 28 days to mimic the effects of GH doping.
Endocrinologist Dr Cathy McHugh, who is leading the study, told BBC News Online: "In general, the levels of proteins are huge in comparison to the levels people produce themselves."
Dr Richard Holt, who is also working on the research, added: "Although there are highly sophisticated methods for detecting the abuse if anabolic steroids and related substances, no such methods have yet been devised for testing for abuse with GH."
A spokesperson for UK Sport, the body responsible for promoting ethically fair and drug-free sport in the UK, said of growth hormones: "Competitors may use these substances for various reasons depending on the substance and the desired result.
"These can include: stimulating the production of naturally occurring hormones; increasing muscle size and strength; helping repair body tissue, leading to quicker recovery from injuries; and improving the blood's ability to carry oxygen, particularly relevant for endurance competitors such as marathon runners and cyclists.
"Since 1988 there have been only nine findings for peptide hormones among competitors tested as part of the UK's anti-doping programme - one in football, two in athletics, two in cycling, three in powerlifting and one in rugby league."
Anyone interested in participating in the study should contact Dr McHugh on 023 8079 4265 or Dr Richard Holt on 023 8079 4665.