Growth hormone status during long-term hexarelin therapy

Area of Science:

• Endocrinology
• Pharmacology

Background:

• Hexarelin is a potent growth hormone (GH)-releasing peptide with known efficacy via various administration routes.
• The long-term effects of hexarelin on GH levels in adults remained uncharacterized.

Purpose of the Study:

• To investigate the impact of 16 weeks of twice-daily subcutaneous hexarelin administration on GH response in adults.
• To assess the reversibility of GH response attenuation after hexarelin cessation.
• To evaluate chronic hexarelin effects on the GH-IGF-I axis, bone metabolism, body composition, and bone mineral density.

Main Methods:

• 16 weeks of twice-daily subcutaneous hexarelin (1.5 µg/kg BW) administration.
• GH response measured via area under the curve (AUCGH) at baseline, weeks 1, 4, 16, and 20 (4 weeks post-therapy).
• Assays for serum IGF-I, IGFBP-3, bone formation/resorption markers, body composition, and bone mineral density.

Main Results:

• Significant decrease in AUCGH at weeks 4 and 16 compared to baseline (P < 0.05 and P < 0.01).
• AUCGH significantly recovered by week 20 (P < 0.05 vs. week 16) and was not different from baseline.
• No significant changes in serum IGF-I, IGFBP-3, body composition, or bone mineral density.
• Increased serum C-terminal propeptide of type I collagen at week 16 (P = 0.019).

Conclusions:

• Chronic hexarelin therapy leads to a partial and reversible attenuation of GH response.
• The studied hexarelin regimen demonstrated minimal biological impact on the GH-IGF-I axis.
• Further research is warranted to explore the therapeutic potential of chronic hexarelin administration.