title: Growth hormone in sports: detecting the doped or duped.
abstract: BACKGROUND
  Doping with growth hormone (GH) is banned; however, there is anecdotal evidence that it is widely abused. GH is reportedly often used in combination with anabolic steroids at high doses for several months. Development of a robust test for detecting GH has been challenging since recombinant human 22-kDa GH used in doping is indistinguishable analytically from endogenous GH and there are wide physiological fluctuations in circulating GH concentrations.
  
  
  CONCLUSIONS
  One approach to GH testing is based on measurement of different circulating GH isoforms using immunoassays that differentiate between 22-kDa and other GH isoforms. Administration of 22-kDa GH results in a change in its abundance relative to other endogenous pituitary GH isoforms. The differential isoform method is, however, limited by its short time window of detection. A second approach that extends the time window of detection is based on detection of increased levels of circulating GH-responsive proteins, such as the insulin-like growth factor (IGF) axis and collagen peptides. As age and gender are the major determinants of variability for IGF-I and the collagen markers, a test based on these markers must take these factors into account. Extensive data now validate the GH-responsive marker approach, and implementation is largely dependent on establishing an assured supply of standardized assays.
  
  
  CONCLUSIONS
  Robust tests are available to detect GH and enforce the ban on its abuse in sports. Novel approaches that include gene expression and proteomic profiling must continue to be pursued to expand the repertoire of testing approaches available and to maintain deterrence of GH doping.
authors.affiliation: Pituitary Research Unit, Garvan Institute of Medical Research, Sydney, NSW, Australia. Ken_Ho@health.qld.gov.au
authors.forename: Ken K Y
authors.initials: KK
authors.lastname: Ho
authors.forename: Anne E
authors.initials: AE
authors.lastname: Nelson
mesh_terms: D000367:Age Factors; D000911:Antibodies, Monoclonal; D024042:Collagen Type I / Q000097:blood; D004300:Doping in Sports / Q000379:methods / Q000517:prevention & control; D005260:Female; D019382:Human Growth Hormone / Q000032:analysis / Q000097:blood* / Q000652:urine; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D010446:Peptide Fragments / Q000032:analysis* / Q000097:blood; D010455:Peptides / Q000097:blood; D020033:Protein Isoforms / Q000097:blood*; D040901:Proteomics / Q000379:methods; D011994:Recombinant Proteins / Q000097:blood*; D015813:Substance Abuse Detection / Q000379:methods*
chemical_list: D000911:Antibodies, Monoclonal; D024042:Collagen Type I; C515497:IGFBP3 protein, human; D018972:Insulin-Like Growth Factor Binding Protein 3; D010446:Peptide Fragments; D010455:Peptides; D020033:Protein Isoforms; D011994:Recombinant Proteins; C052929:collagen type I trimeric cross-linked peptide; C404802:human growth hormone 22K; C039519:somatotropin 20K; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I