Growth hormone-releasing hormone reverses secondary somatotroph unresponsiveness

Area of Science:

• Pediatric Endocrinology
• Growth Hormone Therapy
• Hormone Replacement

Background:

• Severe growth hormone deficiency (GHD) in prepubertal children presents significant growth challenges.
• Assessing pituitary responsiveness to growth hormone-releasing hormone (GHRH) is crucial for treatment efficacy.

Purpose of the Study:

• To evaluate the effect of GHRH 1-44 treatment on pituitary GH secretion and growth velocity in severely GHD children.
• To explore the relationship between GHRH stimulation, growth response, and patient characteristics.

Main Methods:

• Twenty prepubertal children with severe GHD received subcutaneous GHRH 1-44 (10 mcg/kg) for six months, either daily or thrice weekly.
• Acute intravenous GHRH tests were conducted before, and at 2 and 6 months of treatment to measure peak GH responses.
• Growth velocity (GV) was monitored throughout the treatment period.

Main Results:

• Mean peak GH responses to acute GHRH tests significantly increased from baseline (2.92 mcg/L) to 6 months (7.56 mcg/L) (P < 0.05).
• Mean growth velocity during treatment was 2.99 cm/yr, with only two patients showing >2 cm/yr increase.
• A positive correlation was observed between GV and pre-treatment peak GH response (r=0.68, P < 0.005), and a negative correlation between GH response and bone age (r=-0.46, P < 0.05).

Conclusions:

• Six months of GHRH treatment can enhance pituitary responsiveness in some severely GHD children, even those initially unresponsive.
• The duration and severity of GHD may influence the somatotrophs' ability to respond to GHRH stimulation.
• GHRH therapy shows potential for improving pituitary function in select GHD pediatric populations.