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Diagnostic value of the growth hormone-releasing factor stimulation test
C H Albini1, E O Reiter, B J Mills
1Department of Pediatrics, Children's Hospital, Buffalo, NY 14222.
Insights
Growth hormone-releasing factor (GRF) testing effectively identifies severe growth hormone (GH) deficiency in children. GRF unresponsiveness predicts severe GH deficiency, while responses offer insights into partial deficiency and idiopathic growth failure.
Area of Science:
- Pediatric Endocrinology
- Growth Hormone Physiology
- Clinical Diagnostics
Background:
- Growth failure in children necessitates accurate diagnosis of growth hormone (GH) deficiency.
- Growth hormone-releasing factor (GRF) is a key stimulant for GH secretion.
- Differentiating causes of growth failure requires reliable diagnostic tools.
Purpose of the Study:
- To evaluate the diagnostic utility of growth hormone-releasing factor (GRF) in assessing growth hormone (GH) deficiency in children.
- To compare GH responses to GRF across different pediatric growth failure etiologies.
- To determine if GRF unresponsiveness predicts severe GH deficiency.
Main Methods:
- Assessed GH responses to GRF in 55 children with growth failure.
- Categorized patients into four groups: severe GH deficiency, partial GH deficiency, prior cranial radiation, and idiopathic growth failure.
- Utilized ANOVA and post-hoc tests (Scheffe, Student-Newman-Keuls) to analyze group differences.
Main Results:
- Children with severe GH deficiency showed no significant GH response to GRF (1.6 ng/ml).
- Partial GH deficiency (17.2 ng/ml) and prior cranial radiation (10.4 ng/ml) groups exhibited moderate GH responses.
- Idiopathic growth failure group demonstrated the highest GH response to GRF (35.9 ng/ml).
- Significant differences in GH response were observed between groups (p < 0.01).
Conclusions:
- GRF unresponsiveness is a reliable indicator of severe GH deficiency in children.
- GRF testing provides semiquantitative information on somatotrope responsiveness in partial GH deficiency and idiopathic growth failure.
- GRF stimulation test aids in diagnosing and understanding the pathophysiology of pediatric growth failure.
Abstract:
Growth hormone (GH) responses to growth hormone-releasing factor (GRF) were evaluated in 55 children with growth failure. The study groups consisted of group 1, severe GH deficiency; group 2, partial GH deficiency; group 3, patients with prior cranial radiation for nonpituitary brain tumors; and group 4, children with idiopathic growth failure. Children in group 1 were unresponsive to GRF (mean GH peak +/- SEM, 1.6 +/- 0.5 ng/ml). Higher GH responses to GRF were observed in both groups 2 (17.2 +/- 4.1 ng/ml) and 3 (10.4 +/- 2.8 ng/ml). The highest GH responses to GRF were observed in group 4 (35.9 +/- 4.3 ng/ml). ANOVA revealed a significant difference between groups (F = 12.9; df = 3; p less than 0.01), and further analysis by the Scheffe and Student-Newman-Keuls tests revealed that group 4 was significantly higher than groups 1, 2, or 3 (p less than 0.05). These data suggest that GRF unresponsiveness is a reliable predictor of severe GH deficiency. In patients with partial GH deficiency or idiopathic growth failure, the GRF gives semiquantitative information about somatotrope responsivity to exogenous stimulation.