Suppression and recovery of GH secretion after GH injection in non-GH deficient short children.
OBJECTIVE
To identify the effect of exogenous GH on endogenous GH secretion in 48 non-GH deficient short children participating in a placebo-controlled trial of GH therapy on final adult height.


METHODS
Night GH secretion (mean of levels every 20 min from 20.00 to 08.00 h) was evaluated at baseline, 6 months before starting placebo or GH (somatotropin, 0.222 mg/kg/ week, divided into 3 doses each week). At 6 months after starting injections, blood samples for GH were obtained hourly for 24 h after an injection, and every 20 min on each of the next two nights (with no additional placebo or GH injection).


RESULTS
IGF-I levels in the treatment group were elevated at 12 and 24 h but not at 36 h compared to the placebo group. Mean GH levels in the placebo group did not vary significantly among the four sampling periods. In the treatment group, the mean serum GH rose to a supraphysiological peak at an average time of 4 h after injection. Subsequently, mean GH level was significantly suppressed compared to placebo on the second night following GH injection, but returned to normal by the third night.


CONCLUSIONS
After 6 months of a thrice weekly GH treatment regimen in non-GH deficient short children, endogenous GH secretion was reduced from 24 to 36 h after injection compared to placebo and returned to control levels by 48 to 60 h after injection.
Rose
S R
SR
University of Tennessee, Memphis, USA.
Baron
J
J
Bernstein
D
D
Yanovski
J
J
Troendle
J F
JF
Leschek
E
E
Chipman
J
J
Cutler
G B
GB
D002648:Child; D005260:Female; D013006:Growth Hormone / Q000008:administration & dosage / Q000172:deficiency / Q000378:metabolism*; D006801:Humans; D007279:Injections, Subcutaneous; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male
D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone