Interrelationship between insulin, leptin and growth hormone in growth hormone-treated children.
OBJECTIVE
The aim of the study was to examine insulin homeostasis during growth hormone (GH) therapy, and to investigate the effect of GH treatment on insulin and leptin concentration in obese children.


METHODS
Nineteen obese children (8 with Prader-Willi Syndrome (PWS)) were treated with GH 0.1 IU/kg/day dose for 3 months and were compared with 29 non-treated age and sex matched obese children (9 PWS) and 49 GH treated non-obese short children. Mean age of the children was 10.3+/-1.8 (6.7-13.8) y, with body mass index of 23.6+/-10.4 (11.5-47) kg/m2.


RESULTS
Leptin concentration decreased and was correlated inversely with initial leptin value (r2=-0.374, P<0.001) and decreased body mass (r2=0.338, P=0.001). Insulin sensitivity index was not significantly changed during therapy. Leptin decrease after 3 months of GH administration was correlated inversely with the increase in first phase insulin response to intravenous glucose tolerance test (IVGTT) (r2=-0.595, P<0.001). Results of long-term follow-up of treated patients demonstrated a decrease in insulin concentration after cessation of therapy. In GH-treated subjects, the glucose increase in response to glucose load appeared to be higher than in untreated subjects.


CONCLUSIONS
The high insulin response to glucose load seen in GH-treated subjects was appropriate to their glucose concentration and the insulin sensitivity index was unchanged relative to the pretreatment period. Increased insulin dosage in our patients did not induce an increase in leptin concentrations as had been hypothesised.
Zadik
Z
Z
Pediatric Endocrine Unit, Kaplan Medical Center, Rehovot, Israel. zadikz@netvision.net.il
Wittenberg
I
I
Segal
N
N
Altman
Y
Y
Zung
A
A
Gross
V
V
Reifen
R
R
D000886:Anthropometry; D016022:Case-Control Studies; D002648:Child; D005260:Female; D005951:Glucose Tolerance Test; D013006:Growth Hormone / Q000097:blood / Q000627:therapeutic use*; D006801:Humans; D007328:Insulin / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D020738:Leptin / Q000097:blood*; D008297:Male; D009765:Obesity / Q000097:blood*; D011218:Prader-Willi Syndrome / Q000097:blood* / Q000188:drug therapy*
D007328:Insulin; D020738:Leptin; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone