Do short children secrete insufficient growth hormone?

Area of Science:

• Pediatric Endocrinology
• Growth Hormone Physiology

Background:

• Short stature in children is a common clinical concern.
• Standard pharmacologic stimulation tests are used to assess growth hormone (GH) secretion.
• However, some children with short stature and normal GH responses to stimulation exhibit poor growth, suggesting limitations in current diagnostic methods.

Purpose of the Study:

• To compare 24-hour integrated GH concentration in children with normal stature versus short children.
• To evaluate the utility of integrated GH concentration in identifying children with impaired spontaneous GH secretion despite normal stimulation test results.
• To determine if integrated GH concentration can better predict response to GH therapy in short children.

Main Methods:

• Collected 24-hour integrated GH concentrations from 46 children of normal stature and 90 short children.
• Classified short children into groups based on standard pharmacologic GH stimulation tests (deficient vs. normal response).
• Statistically compared mean integrated GH concentrations across groups: normal stature, short with normal stimulation, and short with GH deficiency.

Main Results:

• Mean integrated GH concentration was significantly higher in normal stature children (6.6 ng/mL) compared to short children with normal stimulation (3.8 ng/mL) and those with GH deficiency (1.6 ng/mL).
• A significant proportion (45%) of short children with normal stimulation tests had integrated GH concentrations overlapping with the GH-deficient group, suggesting impaired spontaneous secretion.
• This overlap indicates a spectrum of spontaneous GH secretion even in children with normal stimulation responses.

Conclusions:

• Integrated GH concentration provides a more nuanced assessment of spontaneous GH secretion than stimulation tests alone.
• Short children with normal GH stimulation but low integrated GH levels may represent a distinct subgroup with potential for growth hormone therapy.
• Integrated GH concentration may be a superior biomarker for identifying short children who could benefit from growth hormone therapy.