Combined evaluation of resting IGF-I, N-terminal propeptide of type III procollagen (PIIINP) and C-terminal cross-linked telopeptide of type I collagen (ICTP) levels might be useful for detecting inappropriate GH administration in athletes: a preliminary report.
OBJECTIVE
To verify whether combined measurements of GH-dependent parameters might be useful in detecting exogenous recombinant GH (rGH) administration in male athletes from different disciplines.


METHODS
Sixty-six athletes (control group) were sampled for the evaluation of resting IGF-I, N-terminal propeptide of type III procollagen (PIIINP) and telopeptide type I collagen (ICTP). Cut-off values (mean + 2 SD) for IGF-I, PIIINP and ICTP were calculated and arbitrary scores (1.5, 2.0) were assigned to abnormal parameters. By using the sum of individual parameter scores, positive (> or = 3) or negative (< 3) scores were obtained. In addition, a subgroup of six athletes was treated for 3 weeks with rGH (0.09 IU/kg body weight, 6 days/week) and was similarly evaluated at the end of the 1st, 2nd and 3rd week (i.e. 18 samples).


RESULTS
Abnormal IGF-I, or PIIINP or ICTP levels were found, respectively, in one, two and four subjects (1.5-6.1%) of the control group (in the younger athletes); only one 19-year-old subject of this group obtained a positive score. Abnormal IGF-I, PIIINP and ICTP levels were found in 61.1-66.7% samples of the treated group. Positive cases were 3/6 at the 1st and 2nd week and 6/6 at the 3rd week. The sensitivity of the screening approach was 50-100% (at the 1st-2nd and 3rd week, respectively) and specificity was 98.5%.


CONCLUSIONS
This 'first level' screening test is safe, acceptable and relatively inexpensive. Further additional investigations of 'second level' (i.e. GH secretory profile, GH response to a GH-releasing peptide) can be retained to validate or exclude rGH administration or for the early diagnosis of infrequent endogenous GH hypersecretion.
Laboratorio Sperimentale Ricerche Endocrinologiche, Instituto Auxologico Italiano--IRCCS, Milano, Italy. sartorio@auxologico.it
Alessandro
A
Sartorio
Fiorenza
F
Agosti
Nicoletta
N
Marazzi
Nicola A
NA
Maffiuletti
Silvano G
SG
Cella
Antonello E
AE
Rigamonti
Laura
L
Guidetti
Luigi
L
Di Luigi
Eugenio E
EE
Muller
D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D024042:Collagen Type I; D004300:Doping in Sports; D013006:Growth Hormone / Q000494:pharmacology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male; D010446:Peptide Fragments / Q000097:blood*; D010455:Peptides; D011347:Procollagen / Q000097:blood*; D012680:Sensitivity and Specificity; D013177:Sports
D015415:Biomarkers; D024042:Collagen Type I; D010446:Peptide Fragments; D010455:Peptides; D011347:Procollagen; C052929:collagen type I trimeric cross-linked peptide; C041876:procollagen Type III-N-terminal peptide; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone