title: The effect of a period of intensive exercise on the isoform test to detect growth hormone doping in sports.
abstract: OBJECTIVE
  The major objective of this study was to investigate the effects of several days of intense exercise on growth hormone (hGH) testing using the World Anti-Doping Agencies hGH isoform differential immunoassays. Additionally the effects of circadian variation and exercise type on the isoform ratios were also investigated.
  
  
  METHODS
  15 male athletes performed a simulated nine day cycling stage race. Blood samples were collected twice daily over a period of 15 days (stage race+three days before and after). hGH isoforms were analysed by the official WADA immunoassays (CMZ Assay GmbH).
  
  
  RESULTS
  All measured isoform ratios were far below the WADA decision limits for an adverse analytical finding. Changes in the isoform ratios could not be clearly connected to circadian variation, exercise duration or intensity.
  
  
  CONCLUSIONS
  The present study demonstrates that the hGH isoform ratios are not significantly affected by exercise or circadian variation. We demonstrated that heavy, long term exercise does not interfere with the decision limits for an adverse analytical finding.
authors.affiliation: Anti Doping Lab Qatar, PO Box 27775, Doha, Qatar. svoss@adlqatar.com
authors.forename: S C
authors.initials: SC
authors.lastname: Voss
authors.forename: S
authors.initials: S
authors.lastname: Giraud
authors.forename: M
authors.initials: M
authors.lastname: Alsayrafi
authors.forename: P C
authors.initials: PC
authors.lastname: Bourdon
authors.forename: Y O
authors.initials: YO
authors.lastname: Schumacher
authors.forename: M
authors.initials: M
authors.lastname: Saugy
authors.forename: N
authors.initials: N
authors.lastname: Robinson
mesh_terms: D000328:Adult; D004300:Doping in Sports; D015444:Exercise / Q000502:physiology*; D019382:Human Growth Hormone / Q000008:administration & dosage / Q000097:blood*; D006801:Humans; D007118:Immunoassay; D008297:Male; D020033:Protein Isoforms; D015813:Substance Abuse Detection / Q000379:methods*; D013997:Time Factors
chemical_list: D020033:Protein Isoforms; D019382:Human Growth Hormone