Experts believe a new test to detect human growth hormone may bring sports authorities a step closer to catching doping athletes.
The blood test was recently developed by Dr Ken Ho of Sydney's
Garvan Institute of Medical Research, and colleagues, with support
from the World Anti-Doping Agency (WADA).
"This new test is more sensitive to human growth hormone than
what we've had in the past," Ho said. "My message to athletes would
be to train harder instead of cheating."
It has been notoriously difficult to identify athletes illegally
using human growth hormone. Not only is the hormone naturally
produced in the body - making it harder to detect synthetic
versions - but the concentrations of it normally circulating in the
body vary enormously and can disappear within minutes.
Human growth hormone is produced by the pituitary gland and
helps cells regenerate. Synthetic versions of the hormone are
routinely prescribed to children with growth problems, or
tuberculosis and Aids patients who need to maintain their body
It is also widely taken among some anti-ageing advocates since it
can improve skin elasticity. But improper use of the hormone can
lead to problems including the nerve disorder acute carpal tunnel
syndrome, diabetes and unnatural growth of the bones.
Spots suspect proteins
The new test works by finding proteins triggered by the hormone.
"We've been able to identify markers that show abuse by measuring
when other hormones and proteins released by human growth hormone
reach certain levels," said Dr Olivier Rabin, WADA's science
director. Rabin said that these biological markers are not affected
by any other differences between athletes, such as ethnicity,
gender, or physiology.
WADA has already introduced another test, which identifies the
synthetic version of human growth hormone in the body, on a limited
scale. That test was in place at the Athens and Turin Olympic
Games. The agency hopes to use both tests together to maximize
their chances of detection. But finding cheating athletes on a
large scale will be difficult since the hormone can be detected
only in blood - only trace amounts are present in urine. And blood
tests are not used as regularly as urine tests.
While designing the new test, Ho and his colleagues also made
another interesting discovery: human growth hormone doesn't work on
In their research, Ho and colleagues looked at the effects
produced by human growth hormone on its own and in combination with
testosterone, in nearly 100 recreational athletes.
In the study, 64 men were given a placebo, human growth
hormone or testosterone, or a combination of the latter two, for
eight weeks. In the other half of the study, 33 women were given a
placebo or the growth hormone, for eight weeks. Their physical
performances were then tested in various categories, including how
much weight they could lift, how high they could jump and how fast
they could sprint.
Works with testosterone
"We found that growth hormone does not increase muscle mass or
improve performance," Ho said. "Only when you combine growth
hormone with testosterone does it have an effect," he said. When
taken together, the two substances have a synergistic effect,
lowering the body's fluid and fat levels while building muscle.
But the conclusions from Ho's study are limited. Ho acknowledged
that while study participants were given "high but safe" doses of
human growth hormone and testosterone, professional athletes who
are doping would probably use much higher levels for longer
While Ho and colleagues concluded that the differences among
athletes on various treatment regimens were not statistically
significant, some experts think the differences cannot be
"In the laboratory, very small differences may not be
significant for scientists," said Dr Charles Yesalis, professor
emeritus of health and human development at Pennsylvania State
University. "But we can't always measure small differences that are
unbelievably important in sport." Yesalis was not connected to the
Cocktail of banned substances
Experts also suspect that the vast majority of doping athletes
already use a cocktail of banned substances. "Athletes taking human
growth hormone probably take it in conjunction with a steroid,"
said Dr Todd Schlifstein, a sports medicine rehabilitation
physician at New York University Medical Centre's Rusk Institute.
Human growth hormone is thought to prolong the effects of banned
And because there is not yet any widespread test for human
growth hormone, athletes can continue taking it even when they are
being drug-tested. "This is possibly a way for athletes to maintain
the effects of steroids without taking the chance of getting
caught," Schlifstein said.
With the new tests however, WADA hopes that will no longer be
the case. Rabin said WADA is now working to make the human growth
hormone tests more widely available, and expects them to soon make a
dramatic impact on professional sports.
Others, like Yesalis, are not so sure. "We have heard for years
that a reliable test is coming soon," he said. "When I see athletes
getting smaller and no Olympic or world records being broken,
that's when I'll believe it." – (Sapa-AP)
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