Changes in non-22-kilodalton (kDa) isoforms of growth hormone (GH) after administration of 22-kDa recombinant human GH in trained adult males.
GH is being used by elite athletes to enhance sporting performance. To examine the hypothesis that exogenous 22-kDa recombinant human GH (rhGH) administration could be detected through suppression of non-22-kDa isoforms of GH, we studied seventeen aerobically trained males (age, 26.9 +/- 1.5 yr) randomized to rhGH or placebo treatment (0.15 IU/kg/day for 1 week). Subjects were studied at rest and in response to exercise (cycle-ergometry at 65% of maximal work capacity for 20 min). Serum was assayed for total GH (Pharmacia IRMA and pituitary GH), 22-kDa GH (2 different 2-site monoclonal immunoassays), non-22-kDa GH (22-kDa GH-exclusion assay), 20-kDa GH, and immunofunctional GH. In the study, 3 h after the last dose of rhGH, total and 22-kDa GH concentrations were elevated, reflecting exogenous 22-kDa GH. Non-22-kDa and 20-kDa GH levels were suppressed. Regression of non-22-kDa or 20-kDa GH against total or 22-kDa GH produced clear separation of treatment groups. In identical exercise studies repeated between 24 and 96 h after cessation of treatment, the magnitude of the responses of all GH isoforms was suppressed (P < 0.01), but the relative proportions were similar to those before treatment. We conclude: 1) supraphysiological doses of rhGH in trained adult males suppressed exercise-stimulated endogenous circulating isoforms of GH for up to 4 days; 2) the clearest separation of treatment groups required the simultaneous presence of high exogenous 22-kDa GH and suppressed 20-kDa or non-22-kDa GH concentrations; and 3) these methods may prove useful in detecting rhGH abuse in athletes.
Wallace
J D
JD
Metabolic Research Unit, Department of Medicine, University of Queensland, Princess Alexandra Hospital, Brisbane 4102, Australia. jwallace@medicine.pa.uq.edu.au
Cuneo
R C
RC
Bidlingmaier
M
M
Lundberg
P A
PA
Carlsson
L
L
Boguszewski
C L
CL
Hay
J
J
Boroujerdi
M
M
Cittadini
A
A
Dall
R
R
Rosén
T
T
Strasburger
C J
CJ
D000328:Adult; D001642:Bicycling; D019382:Human Growth Hormone / Q000737:chemistry* / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008970:Molecular Weight; D009994:Osmolar Concentration; D010806:Physical Education and Training; D020033:Protein Isoforms / Q000097:blood / Q000737:chemistry / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000494:pharmacology
D020033:Protein Isoforms; D011994:Recombinant Proteins; D019382:Human Growth Hormone