Growth hormone-releasing peptide-2
Growth hormone-releasing peptide-2 has been studied in 8 papers since 2000: 6 trials and 1 observational study in people, 1 review. It has not reached trials in people. The newest paper, Oct 26, 2009: “Pre- versus postmenopausal age, estradiol, and peptide-secretagogue type determine pulsatile growth hormone secretion in healthy women: studies using submaximal agonist drive and an estrogen clamp”.
“Submaximally stimulated pulsatile GH secretion was positively determined by PRE vs. POST age (P < 0.001), E(2) repletion vs. depletion (P = 0.001) and GHRP-2 vs. GHRH stimulation (P < 0.001)”
None of its findings points the other way.
- 2 independent labs in 1 country
- Funders: National Center for Advancing Translational Sciences and 5 more
- Human trial6
- Humans1
Studies in people
3 studies gave growth hormone-releasing peptide-2 to people and measured what changed.
up: Increases pulsatile growth hormone secretionP < 0.001
Randomized trial22 peopleWomenpremenopausal 24 ± 0.8 yr; postmenopausal 63 ± 1.8 yr
Postmenopausal women
The Journal of clinical endocrinology and metabolism, Oct 26, 2009
up: Increases pulsatile growth hormone secretionmore stimulatory than GHRH; P = 0.011 (low E(2)), P < 0.001 (high E(2))
Trial22 peopleWomen
Postmenopausal women; during low and high estradiol
American journal of physiology. Endocrinology and metabolism, May 26, 2009
up: Increases basal (nonpulsatile) GH secretion rate4.4-fold
up: Increases inter-day synchrony of 24-h GH secretory profiles
Randomized trial10 peopleWomen24 h
Postmenopausal women
The Journal of clinical endocrinology and metabolism, Aug 1, 2000
What did studies of Growth hormone-releasing peptide-2 find?
3Studies of Growth hormone-releasing peptide-2 measured 3 outcomes; the most studied are pulsatile growth hormone secretion (2 studies), inter-day synchrony of 24-h GH secretory profiles (1) and basal (nonpulsatile) GH secretion rate (1).
Pulsatile growth hormone secretion
upin humans2
2 studies
Pulsatile growth hormone secretion
upin humans2
Growth hormone-releasing peptide-2 increases pulsatile growth hormone secretion in humans (P < 0.001).
“Submaximally stimulated pulsatile GH secretion was positively determined by PRE vs. POST age (P < 0.001), E(2) repletion vs. depletion (P = 0.001) and GHRP-2 vs. GHRH stimulation (P < 0.001)”
Human trialcompared with GHRH stimulation at a half-maximally stimulatory dose, after adjustment for abdominal visceral fat and basal secretion0.33 mug/kgfemales
The Journal of clinical endocrinology and metabolism
Growth hormone-releasing peptide-2 increases pulsatile growth hormone secretion in humans (compared with GHRH, independent of age; during low and high estradiol) (more stimulatory than GHRH; P = 0.011 (low E(2)), P < 0.001 (high E(2))).
“Independently of age, GHRP-2 was more stimulatory than GHRH during low E(2) (P = 0.011) and high E(2) (P < 0.001).”
Human trialcompared with GHRH, independent of age; during low and high estradiolfemales
American journal of physiology. Endocrinology and metabolism
Inter-day synchrony of 24-h GH secretory profiles
upin humans1
1 study
Inter-day synchrony of 24-h GH secretory profiles
upin humans1
Growth hormone-releasing peptide-2 increases inter-day synchrony of 24-h GH secretory profiles in humans (not with E2 alone).
“Cross-correlation analysis showed that GHRP-2 infusion (but not E2 administration) significantly synchronized paired 24-h serum GH concentration profiles (P < 10(-3))”
Human trialnot with E2 alone1 microg/kg x h24 hfemalesn = 10
The Journal of clinical endocrinology and metabolism
Basal (nonpulsatile) GH secretion rate
upin humans1
1 study
Basal (nonpulsatile) GH secretion rate
upin humans1
Growth hormone-releasing peptide-2 increases basal (nonpulsatile) GH secretion rate in humans (versus saline infusion) (4.4-fold).
“Intravenous GHRP-2 infusion augmented the basal (nonpulsatile) rate of GH secretion by 4.4-fold (P < 10(-4)).”
Human trialversus saline infusion1 microg/kg x h24 hfemalesn = 10
The Journal of clinical endocrinology and metabolism