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Change in the growth hormone (GH) response to GH-releasing factor (GRF) caused by exogenous GH in short children
1Endocrine Research Laboratory, National Children's Medical Research Center, Tokyo, Japan.
Insights
Exogenous growth hormone (GH) administration suppressed GH release in prepubertal children but enhanced it in older boys. This study investigated feedback mechanisms of GH release in pediatric subjects.
Area of Science:
- Pediatric Endocrinology
- Growth Hormone Physiology
- Feedback Regulation
Background:
- Exogenous growth hormone (GH) administration is a common treatment for growth disorders.
- The feedback mechanisms of GH release in children are not fully understood.
- Investigating GH feedback is crucial for optimizing treatment strategies.
Purpose of the Study:
- To determine if exogenous GH administration induces feedback suppression of GH release in children.
- To analyze the impact of GH administration on GH response to growth hormone-releasing factor (GRF).
Main Methods:
- Growth hormone-releasing factor (GRF) tests were conducted before and after a 10-day course of GH administration.
- Sixteen prepubertal and early pubertal boys (aged 5-14 years) with normal GH responses were studied.
- Serum GH levels and integrated areas under the GH curves (GH AUC) were analyzed.
Main Results:
- Exogenous GH suppressed GH response to GRF in prepubertal children (Group A).
- Exogenous GH exaggerated GH response to GRF in older, early pubertal children (Group B).
- GH AUC before treatment correlated negatively with the percent change in GH AUC after treatment (r = -0.742, p < 0.01).
Conclusions:
- Exogenous GH can suppress endogenous GH release in prepubertal children.
- The effect of exogenous GH on GH feedback appears age-dependent.
- These findings highlight differential GH feedback responses in pediatric populations.
Abstract:
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.