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

J Clin Endocrinol Metab. 1999 Oct;84(10):3591-601. doi: 10.1210/jcem.84.10.6037.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Carrier Proteins / blood
  • Exercise*
  • Glycoproteins / blood
  • Human Growth Hormone / administration & dosage
  • Human Growth Hormone / blood*
  • Human Growth Hormone / pharmacology*
  • Humans
  • Insulin-Like Growth Factor Binding Protein 3 / blood
  • Insulin-Like Growth Factor I / analysis
  • Kinetics
  • Male
  • Physical Education and Training*
  • Physical Endurance
  • Recombinant Proteins / administration & dosage
  • Recombinant Proteins / pharmacology
  • Somatomedins / analysis*
  • Sports Medicine / methods
  • Substance-Related Disorders / diagnosis
  • Time Factors


  • Carrier Proteins
  • Glycoproteins
  • Insulin-Like Growth Factor Binding Protein 3
  • Recombinant Proteins
  • Somatomedins
  • insulin-like growth factor binding protein, acid labile subunit
  • Human Growth Hormone
  • Insulin-Like Growth Factor I