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

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 (≥ 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).