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Clinical aspects of GH binding proteins
1Washington University School of Medicine, Department of Medicine, Saint Louis, Missouri.
Acta Endocrinologica
|January 1, 1991
Summary
Growth hormone binding protein (GH-BP) levels in human serum change significantly with age, from undetectable in premature infants to adult levels by age 20. These levels are crucial for diagnosing conditions like Laron-type GH resistance.
Area of Science:
- Endocrinology
- Biochemistry
- Pediatrics
Background:
- Specific binding of 125I-hGH in human serum is mediated by the GH binding protein (GH-BP).
- GH-BP is derived from the extracellular domain of the growth hormone receptor.
- Measurements are typically expressed relative to normal human reference serum (RSGHB).
Purpose of the Study:
- To characterize the normal range of GH-BP levels across different age groups.
- To investigate the diagnostic utility of GH-BP measurements in endocrine disorders.
- To explore the relationship between GH-BP, growth, and IGF-I in specific populations.
Main Methods:
- Gel filtration methods were primarily used for GH-BP measurements.
- Levels were standardized using a normal human reference serum (RSGHB).
- Comparison of RSGHB across neonatal, childhood, and adult populations.
Main Results:
- RSGHB is undetectable in premature infants, low in term infants, and rises progressively through childhood to adult levels by age 20.
- GH deficiency or excess has minimal impact on RSGHB levels.
- RSGHB is virtually undetectable in Laron-type GH resistance, confirming the diagnosis.
- African pygmies show a failure of RSGHB to rise in late childhood, correlating with decreased IGF-I and growth velocity.
Conclusions:
- GH-BP levels exhibit distinct age-dependent patterns.
- GH-BP measurement is a valuable diagnostic tool for GH resistance.
- Further research into GH-BP abnormalities in various medical conditions is warranted, aided by improved assay methods.