Further evaluation of IGF-I responsiveness to ACTH in children affected with IGHD.
In our previous studies we had demonstrated that, in children affected with isolated GH deficiency (IGHD), a short-term recombinant growth hormone (rGH) therapy increases the 11-deoxycortisol (S) secretion and induces an IGF-I responsiveness to the ACTH challenge. The aim of the present study was to further investigate the mechanisms by which IGF-I is secreted after ACTH challenge in children affected with IGHD by correlating IGF-I versus cortisol (F) time courses after ACTH administration. Ten children affected with IGHD were subjected to rGH therapy (4 IU/day subcutaneously) for 10 days. The responsiveness of IGF-I, F and S to the ACTH 1-17 test were evaluated before and at the end of the therapy. No IGF-I response to the ACTH test was recorded in the patients before the rGH treatment, whereas after rGH administration ACTH induced a significant IGF-I release (p < 0.001) which started at the 1st hour, reached a peak value between the 5th and 6th hours and disappeared at the 10th hour. In conclusion, our study confirms that a short-term rGH therapy induces an IGF-I responsiveness to ACTH and helps to better define the kinetics and the mechanism of this IGF-I response to ACTH.
Merola
B
B
Chair of Endocrinology, 2nd School of Medicine, University of Naples, Italy.
Rossi
E
E
Longobardi
S
S
Selleri
A
A
Esposito
V
V
Colao
A
A
Cataldi
M
M
Ferone
D
D
Lombardi
G
G
D000324:Adrenocorticotropic Hormone; D002648:Child; D002675:Child, Preschool; D005260:Female; D013006:Growth Hormone / Q000172:deficiency* / Q000627:therapeutic use*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D011994:Recombinant Proteins / Q000627:therapeutic use
D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D000324:Adrenocorticotropic Hormone; D013006:Growth Hormone; D006854:Hydrocortisone