How do we best measure growth hormone action?

Area of Science:

• Endocrinology
• Pediatrics
• Metabolic Disorders

Background:

• Growth hormone (GH) is a potent anabolic hormone influencing growth and metabolism.
• Assessing GH therapy efficacy involves auxological, biochemical, and body composition parameters.
• Current methods show variability and limited predictive power for GH response.

Purpose of the Study:

• To review and evaluate the parameters used for assessing growth hormone (GH) therapy response.
• To identify the most reliable indicators for predicting and monitoring GH action in children and adults.

Main Methods:

• Review of auxological parameters: height, height velocity (HV), and final adult height.
• Analysis of biochemical markers: nonspecific (glucose, insulin), GH-IGF axis (IGF-I, IGFBP-3), and bone metabolism indices.
• Evaluation of body composition metrics: BMI, body fat, body water, and bone mineral density.

Main Results:

• Auxological measures like height and HV may not always correlate.
• Biochemical markers and body composition changes show modest effects with significant variability.
• GH dose is a significant positive factor across all measured parameters.
• Serum IGF-I emerges as the most consistent and integrated indicator of GH action.

Conclusions:

• Few current tests reliably predict or monitor GH therapy response.
• Serum IGF-I offers the most integrated and reliable assessment of GH activity in both pediatric and adult populations.
• Further research may refine existing markers or identify novel indicators for GH therapy monitoring.