Change in the growth hormone (GH) response to GH-releasing factor (GRF) caused by exogenous GH in short children.
To determine whether exogenous GH induces feedback of GH release in children, growth hormone-releasing factor (GRP) tests were performed before and after 10-day GH administration. Sixteen non-obese short boys, aged 5-14 yr, with normal GH response to pharmacological tests were studied. Mean basal and peak serum GH levels in GRF tests before and after exogenous GH were not significantly different. The subjects were divided into two groups, A and B, according to the percent change in integrated areas under the GH curves in GRF tests (GH AUC) before and after 10-day GH administration. Group A consisted of 6 boys with decreased GH AUC and group B consisted of 10 boys with increased GH AUC. Mean peak GH in GRF tests and mean GH AUC were significantly higher before exogenous GH in group A than in group B. The boys in group A were all prepubertal, while 4 boys in group B had begun their early pubertal change. The mean age in group A (7.8 +/- 1.8 yr) was significantly lower than that of group B (11.9 +/- 2.4 yr). GH AUC before exogenous GH showed a significant correlation with the percent change in AUC (= -0.742, p less than 0.01). These data demonstrated that the exogenous GH suppressed the GH response to GRF in prepubertal children with good response to GRF before exogenous GH, while it exaggerated the GH response to GRF in older children with relatively poor response before GH.
Tanaka
T
T
Endocrine Research Laboratory, National Children's Medical Research Center, Tokyo, Japan.
Yano
H
H
Umezawa
S
S
Ohmae
Y
Y
Hashimoto
N
N
Miki
Y
Y
Kagawa
J
J
Tanae
A
A
Hibi
I
I
D000293:Adolescent; D000375:Aging / Q000378:metabolism; D001827:Body Height / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D013006:Growth Hormone / Q000097:blood* / Q000494:pharmacology; D013007:Growth Hormone-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007267:Injections; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male
D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone