Questions & Answers on Human Growth Hormone (hGH)

(Read also the special feature on hGH research and detection from Play True - Issue 2 – 2007)

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What is hGH?

Human growth hormone (hGH) is a hormone that is naturally produced by the body. It is synthesized and secreted by cells in the anterior pituitary gland located at the base of the brain.

hGH is known to act on many aspects of cellular metabolism and is also necessary for skeletal growth in humans.

The major role of hGH in body growth is to stimulate the liver and other tissues to secrete insulin like growth factor (IGF-1). IGF-1 stimulates production of cartilage cells, resulting in bone growth and also plays a key role in muscle and organ growth.

hGH is prohibited both in- and out-of-competition under WADA’s List of Prohibited Substances and Methods.


What effect can hGH have on athletic performance?

Literature and research have shown in particular that hGH has an ergogenic and anabolic impact, and that it enhances the anabolic power of steroids.


What are the side effects of hGH abuse?

Commonly reported side effects for hGH abuse are: diabetes in prone individuals; worsening of cardiovascular diseases; muscle, joint and bone pain; hypertension and cardiac deficiency; abnormal growth of organs; accelerated osteoarthritis.

In untreated acromegalic individuals (known for pathological over-production of hGH), many of the symptoms described above are observed and life expectancy is known to be significantly reduced.

Because of the role that hGH plays in stimulating IGF-1 secretion, excessive use of hGH may also lead to metabolic dysfunction, including glucose intolerance and other side effects associated with excess levels of IGF-1.


Does a test for hGH exist?

A test for hGH was first introduced at the 2004 Summer Olympic Games in Athens, Greece. The test to detect hGH abuse is a blood test.


Is the hGH test reliable?

The current test, based on immunoassays, is robust and reliable.

Another blood test, in its final development stage, will be combined with the current test to further enhance the detection window for hGH abuse. This test, the development of which has been partly funded by WADA, is based on biomarkers.

The concepts and development of both hGH tests have been systematically reviewed by international independent experts in such fields as hGH, endocrinology, immunoassay, analytical chemistry, pharmacology, laboratory work, anti-doping, etc, and published in international scientific journals.

Research was initiated by the International Olympic Committee (IOC) and the European Union, and then taken over by WADA – created in late 1999 – when it launched its scientific research program in 2001.


Why has there been only a limited implementation of the hGH test?

The current test is based on the blood matrix and was initially implemented on a limited scale to a number of the WADA-accredited anti-doping laboratories worldwide.

The antibodies used for the current tests were initially produced in a research environment. The production of antibodies in a research environment is characteristically small.

Industrial production of the anti-bodies was the following step for the widespread implementation of the hGH test.

Efforts made by WADA for widespread production of antibodies needed for hGH detection were slowed following the take-over of the company with which WADA had an agreement for the development of these antibodies, and the decision made by the company’s new management in 2006 to stop its cooperation with WADA.

WADA subsequently found a new partner for the large scale production and distribution of antibodies kits.


When will the biomarker-based detection method be implemented?

Following its policy, WADA does not disclose the moment when new detection methods are implemented.

Generally speaking, there is a robust development process to be followed from the research stage to the implementation of a detection method that is fit for anti-doping purpose.

In addition, before implementing any detection method, WADA needs to ensure that it can withstand scientific and legal challenge.


Have there been doping cases involving hGH?

Yes. In addition to a number of cases involving possession of hGH, UK Anti-Doping (UKAD) announced on February 22, 2010, the first completed case involving an analytical finding for hGH. On September 8, 2010, the Canadian Centre for Ethic in Sport (CCES) announced the first case involving an adverse analytical finding for hGH in North America.

Click here for UKAD’s press release.

Click here for WADA’s statement on this case.

Click here for the CCES press release.


Why have there been so few analytical cases for hGH so far?

The test was introduced at the Athens Olympic Games in 2004 and other major sport events. However, the vast majority of tests conducted by anti-doping organizations were in-competition. (WADA is not a testing agency.) Because hGH is often taken by doping athletes out-of-competition to optimize performance, the test is most effective when implemented in a no-advance-notice out-of-competition strategy.

In addition, in order to ensure that any doping case brought forward can withstand scientific and legal challenge, the criteria required for an adverse analytical result for hGH have been very conservative.

Enhanced use of intelligence and strategic testing by anti-doping organizations, as well as tighter positivity criteria as science advances, should help better detect hGH abuse.


Is a urine test for hGH likely to be developed?

According to the majority of international experts, the blood matrix is the most suitable matrix for the detection of hGH.

hGH in urine is found in extremely small quantities (less than 1% than that found in blood).

WADA is collaborating with research teams to explore the development of urine-based detection methods for hGH.


Can blood samples be stored?

Freezing liquid fraction of blood (serum or plasma) is a scientifically acceptable solution that allows for the preservation of substances in samples for future testing and detection.

Research has shown that hGH is very stable in frozen serum or plasma.

WADA encourages anti-doping organizations under the World Anti-Doping Code to store blood samples when relevant.

Storing serum or plasma for future testing has a significant deterrent effect.

The World Anti-Doping Code makes it possible to open a disciplinary proceeding within eight years from the date an anti-doping rule violation occurred.

  • Last Updated September 2011
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