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Plasma IGFBP-3 and its relationship with quantitative growth hormone secretion in short children
M Phillip1, S A Chalew, A A Kowarski
1Department of Pediatric Endocrinology, University of Maryland School of Medicine, Baltimore.
Insights
Serum IGFBP-3 levels in short children correlate strongly with IGF-I and increase with puberty. These levels show a weak link to peak growth hormone (GH) but not integrated GH, impacting diagnostic classifications.
Area of Science:
- Pediatric Endocrinology
- Growth Hormone Secretion
- Biomarker Analysis
Background:
- Short stature in children necessitates accurate assessment of growth hormone (GH) secretion and related factors.
- Insulin-like growth factor-binding protein 3 (IGFBP-3) is a key mediator in the GH-IGF-I axis.
- Understanding the relationship between IGFBP-3, IGF-I, and GH secretion is crucial for diagnosing growth disorders.
Purpose of the Study:
- To evaluate the association between serum IGFBP-3 levels and Insulin-like Growth Factor-I (IGF-I) in poorly growing children.
- To assess the relationship between serum IGFBP-3 levels and quantitative measures of GH secretory status.
- To determine how IGFBP-3 levels relate to pubertal maturation in short children.
Main Methods:
- Studied 102 short children (mean age 11.7 years) with short stature (mean height SDS -2.6).
- Assessed quantitative GH secretory status using 24-hour integrated GH and peak GH response to stimulation tests (arginine and insulin).
- Measured serum GH, IGF-I, and IGFBP-3 levels via radioimmunoassay; IGFBP-3 levels were converted to SD scores (SDS) adjusted for age and gender.
Main Results:
- IGFBP-3 SDS showed a strong positive correlation with IGF-I SDS (r = 0.64, P < 0.0001).
- IGFBP-3 SDS demonstrated a weak positive correlation with peak GH response (r = 0.28, P < 0.0004) but no significant correlation with integrated GH (r = 0.07, P < 0.46).
- IGFBP-3 SDS significantly increased with pubertal maturation (P < 0.0001), with no differences observed based on GH test subgroupings.
Conclusions:
- Serum IGFBP-3 levels in short children are strongly linked to IGF-I levels and increase with puberty.
- IGFBP-3 shows a weak association with peak GH stimulation response but not with integrated GH measurements.
- Diagnostic classifications based on quantitative GH secretion and IGFBP-3 measurements may differ, highlighting the complexity of growth assessment.
Objective:
We assessed the relationship between serum IGFBP-3 levels with IGF-I and quantitative GH secretory status in poorly growing children.
Design:
We studied the relationship between 24-hour integrated concentration of GH, peak GH to paired sequential stimulation tests, IGF-I and the IGFBP-3 serum levels.
Patients:
One hundred and two children (82 males, 20 females, age 11.7 +/- 2.7 years) with short stature (height -2.6 +/- 0.7 SDS) were studied.
Measurements:
Quantitative GH secretory status was assessed by the 24-hour integrated GH and by response to arginine and insulin stimulation. GH, IGFBP-3 and IGF-I were measured by radioimmunoassay. To adjust for age and gender, IGFBP-3 levels were converted to SD score.
Results:
IGFBP-3 SDS was strongly correlated with IGF-I SDS (r = 0.64, P < 0.0001), and weakly with peak GH (r = 0.28, P < 0.0004), but not with the integrated GH concentration (r = 0.07, P < 0.46). IGFBP-3 SDS increased with pubertal maturation (P < 0.0001). There was no difference in mean IGFBP-3 SDS in subgroupings of the patients based on the results of their quantitative GH tests.
Conclusion:
In short children, IGFBP-3 levels increase with puberty, are strongly correlated with IGF-I levels, weakly correlated with peak response to GH stimulation tests, but not correlated with integrated GH. Consequently, diagnostic classifications of patients based on quantitative measurements of GH secretion and IGFBP-3 differ.