The insulin-like growth factor-I (IGF-I) generation test as an indicator of growth hormone status.
OBJECTIVE
The aim of the study was to evaluate the IGF-I generation test (IGF-I gen) as a possible indirect test of Growth Hormone (GH) secretory status.


METHODS
Sixty-five GH deficient (GHD 1 and 2) and 86 control children were studied. Children in the GHD-1 subgroup (n=33) had low GH values (<10 microg/L) after clonidine and levo-dopa while those in the GHD-2 subgroup (n=32) had normal GH values after pharmacologic provocation but low 24-hour GH secretory rates compared to 187 Normal Statured (NS) children. Of the 86 controls, who underwent IGF-I gen,50 were NS and 36 Short-Statured (SS). Serum IGF-I was measured prior to and daily during hGH administration (hGH 0.033 mg/kg/dayx4 days).


RESULTS
The prepubertal and pubertal GHD-1 and GHD-2 children had low baseline IGF-I values but their peak IGF-I values during the IGF-I gen reached those of the controls. The percent increase of IGF-I during the test was greater in the GHD groups than in the controls; in the prepubertal groups: 516+/-58% in the GHD-1, 433+/-50% in the GHD-2, 106+/-12% in the NS, and 102+/-18% in the SS (p=0.001); in the pubertal groups: 191+/-28% in the GHD-1, 141+/-20% in the GHD-2, 48+/-8% in the NS, and 61+/-17% in the SS (p=0.003).


CONCLUSIONS
The IGF-I response during the IGF-I gen seems to reflect the GH status in children.
Spiliotis
Bessie E
BE
Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, University of Patras, School of Medicine, Rion, Patras, Greece. besspil@endo.gr
Alexandrides
Theodore K
TK
Karystianos
Christoforos
C
Vassilakos
Pavlos
P
Zadik
Zvi
Z
Nikolakopoulou
Nikoleta M
NM
Nikiforidis
George
G
Beratis
Nicholas G
NG
D000293:Adolescent; D000704:Analysis of Variance; D016022:Case-Control Studies; D002648:Child; D003940:Diagnostic Techniques, Endocrine; D005260:Female; D006130:Growth Disorders / Q000097:blood* / Q000175:diagnosis / Q000188:drug therapy; D019382:Human Growth Hormone / Q000097:blood / Q000172:deficiency* / Q000627:therapeutic use; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000378:metabolism; D008297:Male; D016555:Matched-Pair Analysis; D008954:Models, Biological; D011627:Puberty / Q000097:blood*; D012016:Reference Values; D018709:Statistics, Nonparametric; D013268:Stimulation, Chemical
D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I