Detecting growth hormone abuse in athletes

The availability of recombinant growth hormone (rGH) for treatment of GH deficiency in 1983 was a major step forward for patients, making treatment more safe and effective. However, the drug immediately also made its way into the arena of sport. Data demonstrating the efficacy of GH in healthy subjects are scarce, and experts continue to discuss if GH has any performance-enhancing effects in trained healthy athletes. But there is no doubt that GH is used by athletes. Several former athletes have confessed abuse of rGH, and ampoules containing GH have been found in the possession of athletes and trainers. Although scientific studies supporting the performanceenhancing effects of GH in trained healthy individuals might be missing, the rumors about its tremendous efficacy appear to be seducing. Consequently, the International Olympic Committee (IOC) banned GH in 1989, and GH is still listed as a banned substance on the World Anti-Doping Agency’s (WADA) 2008 prohibited list. Since the mid 1990s, the IOC and national doping control authorities have funded research projects to develop a test method to detect doping with GH. Later, WADA took over leadership in coordinating the research projects. Since the beginning, researchers mainly followed two different approaches, namely the ‘‘marker approach’’ and the ‘‘isoform approach.’’ It took until the summer of 2004, during the Olympic Games in Athens, when a test to detect GH doping was officially introduced. The development did not stop, and both strategies are subjects of ongoing research projects to validate and improve the methods. This article describes the difficulties associated with developing a test to detect GH doping, and shows the progress made until today.