Bike Pure talks to UKADA about new Human Growth Hormone Test

Earlier this year, the first ever positive test result for Human Growth Hormone was publicized as a break through for clean sport. Now, Bike Pure has spoken with the UK Anti-Doping Agency about the test and what it means for sport and cycling. Following is their interview, republished with permission:

There has been much publicity recently regarding the new test for the banned Human Growth Hormone. It has long been the case that some riders have abused this substance, yet there was never a sufficient, reliable blood test to determine if a rider had been using it, until now that is.

After many months of research and development, a test was finally put into place and British Rugby player Terry Newton became the first athlete to return a positive test for the substance from a blood sample.

The Human Growth Hormone (hGH) test was initially developed in Germany by Dr. Christiaan Strasburger and Dr Martin Bidlingmaier. We were in contact with the UK Anti-doping Agencies Michael Stow this week to help provide us with more information regarding this major breakthrough in anti-doping and asked him how the test was developed.

“UK Anti-Doping (formerly UK Sport) have been collecting blood on a routine basis since 2007 and had requested the use of this test to look for Growth Hormone at times when detection was thought to be most probable,” Stow said. “UK Anti-Doping has hosted and participated in the two previous WADA Growth Hormone Expert group meetings. The majority of work for the development of this test has been done with the support of this group by those mentioned above. The UK WADA accredited laboratory at King’s college London has been fully involved in the validation work of the test.”

The full implementation of this new test is a major breakthrough for anti-doping as a whole, and the process of development to bring about such a test was extensive, rigorous and peer reviewed. We asked Michael Stow what were the major effects of taking the drug. “There are many advantages to using such a drug for riders wishing to dope. When administered as a replacement therapy for growth hormone deficiency, Growth Hormone increases lean mass, reduces fat and increases strength. It is primarily for these reasons that healthy individuals, including elite athletes, have used it in an attempt to improve their physical and sporting performance.”

In a similar way to EPO, Growth Hormone is a naturally occurring substance within our bodies, which makes detection more difficult. I asked Michael to explain in simple terms how they determine a positive test. “Endogenous (our own) Growth Hormone exists as multiple isoforms; 70% of circulating GH is in the form of a 22 kDa polypeptide whereas 5–10% occurs as a 20 kDa isoform. There are also various other forms of GH circulating in our bodies. By contrast injected GH comprises solely the 22 kDa isoform. When Growth Hormone is injected, endogenous secretion of GH is suppressed through a negative feedback mechanism. This test employs two assays, one which measures the 22 kDa polypeptide form of GH and the other that is non-selective for all GH isoforms. This ratio changes when GH is injected and endogenous GH suppressed with 22 kDa GH becoming predominant. Using the ratio of these two assays, thresholds have been established to determine an
Adverse Analytical Finding.”

As with tests for other performance enhancing substances, there is a time frame that the drug remains within an athletes system. When taken as a drug, Growth Hormone is rapidly excreted from the athlete’s body and this gives only a short window of detection, a period of days as opposed to weeks, although Stow revealed an interesting development. “UK Anti-Doping are also working with a research team in Southampton University to develop a second growth hormone test that looks at the downstream markers of GH abuse. This should provide us with a longer window of detection and again will be based on statistical cut-offs to establish doping.” So laboratories are already working on new tests which is terrific news for anti-doping.

With the European cycling season well underway I ask if will we see the new test used to its full extent this season, “The test is already being used in competition. That said, because of the short window of detection the best use of this test is not in competition (when athletes know they are likely to be tested) but for no notice, out of competition testing as UK Anti-Doping have been doing.”

We wish to thank Michael Stokes and the UK Anti-Doping Agency and everyone who was involved in the development and implementation of this ground breaking test in the fight against doping in sport.