title: Responses of the growth hormone (GH) and insulin-like growth factor axis to exercise, GH administration, and GH withdrawal in trained adult males: a potential test for GH abuse in sport.
abstract: GH abuse by elite athletes is currently undetectable. To define suitable markers of GH doping, we assessed the effects of acute exercise, GH administration, and GH withdrawal on the GH/insulin-like growth factor (IGF) axis in athletic adult males. Acute endurance-type exercise increased serum GH, GH-binding protein (GHBP), total IGF-I, IGF-binding protein (IGFBP)-3, and acid-labile subunit (ALS), each peaking at the end of exercise. IGFBP-1 increased after exercise was completed. Free IGF-I did not change with exercise. Recombinant human GH treatment (0.15 IU/kg x day) for 1 week increased serum total IGF-I, IGFBP-3, and ALS, exaggerating the responses to exercise. IGFBP-2 and IGFBP-1 were trivially suppressed. After GH withdrawal, the GH response to identical exercise was suppressed. Total IGF-I, IGFBP-3, and ALS returned to baseline over 3-4 days. In summary, 1) acute exercise transiently increased all components of the IGF-I ternary complex, possibly due to mobilization of preformed intact complexes; 2) GH pretreatment augmented the exercise-induced changes in ternary complexes; 3) postexercise IGFBP-1 increments may protect against delayed onset hypoglycemia; 4) serum total IGF-I, IGFBP-3, and ALS may be suitable markers of GH abuse; and 5) differences in disappearance times altered the sensitivity of each marker for detecting GH abuse.
authors.affiliation: Metabolic Research Unit, Department of Medicine, University of Queensland, Princess Alexandra Hospital, Brisbane, Australia. jwallace@medicine.pa.uq.edu.au
authors.forename: J D
authors.initials: JD
authors.lastname: Wallace
authors.forename: R C
authors.initials: RC
authors.lastname: Cuneo
authors.forename: R
authors.initials: R
authors.lastname: Baxter
authors.forename: H
authors.initials: H
authors.lastname: Orskov
authors.forename: N
authors.initials: N
authors.lastname: Keay
authors.forename: C
authors.initials: C
authors.lastname: Pentecost
authors.forename: R
authors.initials: R
authors.lastname: Dall
authors.forename: T
authors.initials: T
authors.lastname: Rosén
authors.forename: J O
authors.initials: JO
authors.lastname: Jørgensen
authors.forename: A
authors.initials: A
authors.lastname: Cittadini
authors.forename: S
authors.initials: S
authors.lastname: Longobardi
authors.forename: L
authors.initials: L
authors.lastname: Sacca
authors.forename: J S
authors.initials: JS
authors.lastname: Christiansen
authors.forename: B A
authors.initials: BA
authors.lastname: Bengtsson
authors.forename: P H
authors.initials: PH
authors.lastname: Sönksen
mesh_terms: D000328:Adult; D002352:Carrier Proteins / Q000097:blood; D015444:Exercise; D006023:Glycoproteins / Q000097:blood; D019382:Human Growth Hormone / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology*; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007700:Kinetics; D008297:Male; D010806:Physical Education and Training; D010807:Physical Endurance; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D013002:Somatomedins / Q000032:analysis*; D013178:Sports Medicine / Q000379:methods; D019966:Substance-Related Disorders / Q000175:diagnosis; D013997:Time Factors
chemical_list: D002352:Carrier Proteins; D006023:Glycoproteins; D018972:Insulin-Like Growth Factor Binding Protein 3; D011994:Recombinant Proteins; D013002:Somatomedins; C075944:insulin-like growth factor binding protein, acid labile subunit; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I