A robust test for growth hormone doping--present status and future prospects

Area of Science:

• Sports Science
• Biochemistry
• Anti-Doping

Background:

• Growth hormone (GH) doping is a banned practice with anecdotal evidence of widespread abuse, often combined with anabolic steroids.
• Detecting recombinant human 22 kDa (22K) GH is difficult due to its analytical indistinguishability from endogenous GH and physiological fluctuations.
• Current testing methods face limitations in detection window and require further development for reliable anti-doping strategies.

Purpose of the Study:

• To review and discuss current and emerging strategies for detecting growth hormone (GH) doping in athletes.
• To highlight the challenges associated with GH detection and explore novel approaches for improved accuracy and extended detection periods.
• To emphasize the importance of accounting for biological variability in developing effective GH detection methods.

Main Methods:

• Analysis of circulating GH isoforms using immunoassays capable of differentiating between 22K GH and other endogenous isoforms.
• Measurement of GH-responsive proteins, including insulin-like growth factor (IGF) axis and collagen peptides, as indirect markers of GH administration.
• Consideration of age and gender as key determinants for interpreting IGF-I and collagen marker levels in athletes.

Main Results:

• The differential GH isoform method has been implemented but offers a limited detection window.
• The GH-responsive marker approach, utilizing IGF and collagen peptides, shows validation and potential for extended detection.
• Age and gender significantly influence GH-responsive marker levels, necessitating age- and gender-specific reference ranges.

Conclusions:

• GH doping detection requires sophisticated methods that address analytical challenges and physiological variability.
• GH-responsive markers offer a promising avenue for extending the detection window of GH abuse.
• Future anti-doping efforts will likely involve a combination of isoform and marker-based approaches, potentially integrated into an athlete's biological passport.