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Updated: Jun 1, 2026
Comparative Analysis of Human Growth Hormone in Serum Using SPRi, Nano-SPRi and ELISA Assays
Published on: January 7, 2016
Evidence of insulin-like growth factor binding protein-3 proteolysis during growth hormone stimulation testing
Benjamin U Nwosu1, Leslie A Soyka, Amanda Angelescu
1Division of Endocrinology, Department of Pediatrics, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA. benjamin.nwosu@umassmemorial.org
Objectives:
The ternary complex is composed of insulin-like growth factor (IGF)-I, IGF binding protein (IGFBP)-3 and acid labile subunit (ALS). Growth hormone (GH) promotes IGFBP-3 proteolysis to release free IGF-I, ALS, and IGFBP-3 fragments. Our aim was to determine whether elevated GH levels during GH stimulation testing would trigger IGFBP-3 proteolysis.
Design:
This prospective study of 10 short prepubertal children (height standard deviation score -2.37 +/- 0.31) used arginine and GH releasing hormone stimulation to study dynamic changes in the ternary complex moieties. IGFBP-3 was measured in two assays: a radioimmunoassay (RIA) that detects both cleaved and intact IGFBP-3; and an immunochemiluminescence assay (ICMA) that detects only intact IGFBP-3.
Results:
IGFBP-3 measured by RIA increased by 19% (p < 0.05), while IGFBP-3 measured by ICMA did not significantly increase (6.1%).
Conclusion:
The significant increase in IGFBP-3 measured by RIA, but not ICMA, provides evidence of IGFBP-3 proteolysis during acute GH stimulation.
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