Secretagogues govern GH secretory-burst waveform and mass in healthy eugonadal and short-term hypogonadal men

Secretagogues govern GH secretory-burst waveform and mass in healthy eugonadal and short-term hypogonadal men / Johannes D. Veldhuis, Daniel M. Keenan

  • European Journal of Endocrinology 159 (2008) 5 (November), p. 547-554
  • PMID: 18703567
  • PMCID: PMC2680123
  • DOI: 10.1530/EJE-08-0414
  • Erratum in:
    • European Journal of Endocrinology 159 (2008) 6 (December) p. 841
    • DOI: 10.1530/EJE-08-0414e


Background: GH pulses are putatively initiated by hypothalamic GH-releasing hormone (GHRH), amplified by GH-releasing peptide (GHRP), and inhibited by somatostatin (SS).

Objective: To ascertain how secretagogues control the waveform (time evolution of release rates) as well as the mass of secretory bursts.

Design: We quantified the shape of GH secretory bursts evoked by continuous combined i.v. infusion of maximally effective doses of GHRH and GHRP-2, and by bolus injection of each peptide after delivering L-arginine to restrain hypothalamic SS release in 12 healthy young men.

Methods: A mathematically verified and experimentally validated variable-waveform deconvolution model was applied to intensively sampled GH time series.

Results: The secretory-burst mode (time from burst onset to maximal secretion) was 19+/-0.69 min during saline infusion, and fell to a) 10.4+/-3.0 min during constant dual stimulation with GHRH/GHRP-2 (P<0.01), b) 14.6+/-1.8 min after l-arginine/GHRH (P<0.025), and c) 15.0+/-1.0 min after l-arginine/GHRH (P<0.01). Secretagogues augmented the mass of GH secreted in pulses by 44-, 42-, and 16-fold respectively, over saline (2.2+/-0.81 microg/l per h; P<0.001 for each). Pulse number and variability were unaffected. Applying the same methodology to ten other young men with acute leuprolide-induced hypogonadism yielded comparable waveform and mass estimates.

Conclusion: The present analyses in men demonstrate that peptidyl secretagogues modulate not only the magnitude but also the time course of the GH-release process in vivo independently of the short-term sex-steroid milieu.

Original document


Research / Study
14 August 2008
Keenan, Daniel M.
Veldhuis, Johannes D.
United States of America
Other organisations
Mayo Clinic College of Medicine and Science (MCCMS)
Doping classes
S2. Peptide Hormones, Growth Factors
GHRP-2 (pralmorelin)
Growth hormone (GH)
Growth Hormone Releasing Peptide (GHRP)
Growth hormone-releasing hormone (GHRH)
Document category
Scientific article
Document type
Pdf file
Date generated
4 January 2022
Date of last modification
24 January 2022
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