Identification of recombinant equine growth hormone in horse plasma by LC-MS/MS: a confirmatory analysis in doping control.

This research paper presents a successful method to detect the presence of recombinant equine growth hormone (reGH), a suspected doping agent, in racehorse plasma using LC-MS/MS, a kind of chemical analysis.

Background and Purpose

• Equine Growth Hormone (eGH) is an approved drug suspected to be illegally used in racehorses to improve their physical performance and wound healing. The recombinant form of eGH (reGH) is specifically used.
• However, reGH has never been successfully detected at trace concentrations in any biological matrix, making it hard to track its use and regulate it.
• The objective of this study is to propose a highly sensitive and reliable method of detecting and confirming the presence of reGH in racehorses to regulate its use effectively.

Methodology

• An analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was created to detect reGH in horse plasma.
• The plasma sample was treated with ammonium sulfate at the reGH isoelectric point and the resulting pellet was further purified.
• Specific peptides were produced by trypsin digestion and then analysed by LC-MS/MS.

Results

• The method had a detection limit of 1 microgram/L and was validated according to European Union regulation and the Association of Official Racing Chemists requirements.
• The presence of reGH was then successfully detected in a horse’s plasma up to 48 hours after it was administered reGH.
• The LC-MS/MS method can also detect recombinant bovine growth hormone (rbGH) and endogenous eGH. It is the first method with sufficient sensitivity and specificity for these hormones.

Conclusion

• In conclusion, the study presents an efficient analytical tool for detecting reGH in racehorses, which could help in fulfilling the regulation of reGH abuse in the horse racing industry.