GHRP-2

Introduction to GHRP-2

GHRP-2, also identified by the name pralmorelin, is a synthetically produced peptide that functions as a growth hormone secretagogue through activation of ghrelin-associated receptors. As the first compound developed within this pharmacological class, it has played a key role in advancing research into endocrine signaling. GHRP-2 is currently utilized in experimental and diagnostic studies related to hormone deficiency and continues to be explored for its effects on metabolic regulation, muscle maintenance, immune function, and sleep behavior. Its demonstrated oral and sublingual activity in research models differentiates it from many other peptide agents.

Structural Characteristics

GHRP-2 is engineered as a compact peptide molecule optimized for selective receptor interaction within growth hormone signaling pathways.

Research-Observed Effects

1. Muscle Tissue Protection

Animal research indicates that GHRP-2 supports muscle integrity by enhancing protein synthesis while limiting degradation pathways. In growth-restricted yak models, the peptide counteracted muscle loss associated with nutritional stress and environmental hardship. Mechanistically, GHRP-2 reduced the activity of atrogin-1 and MuRF1, proteins involved in muscle protein breakdown. These observations inform broader research into muscle catabolism seen in chronic and degenerative conditions.

2. Appetite Enhancement

GHRP-2 has been consistently shown to increase food consumption in controlled studies. Appetite stimulation is a critical variable in long-term health management research, particularly where disease-related anorexia compromises nutritional status.

3. Cardiac Cell Preservation

Cell-based experiments demonstrate that GHRP-2 reduces programmed cell death in cardiac tissue by supporting mitochondrial stability. Animal studies further suggest that the heart contains specific receptors responsive to this peptide, underscoring its relevance in cardiovascular signaling research.

4. Immune System Support

By stimulating thymic activity, GHRP-2 promotes the maturation of T-cells essential for adaptive immune responses. Since thymic output diminishes with age, peptide-mediated stimulation offers insight into immune rejuvenation and resistance to infection in experimental contexts.

5. Sleep Quality Modulation

Research findings indicate that GHRP-2 increases time spent in deep sleep phases and modifies REM sleep dynamics. These alterations are associated with improvements in cognitive function, recovery, and overall physiological balance, particularly in aging populations.

6. Pain Signaling Interaction

GHRP-2 has demonstrated direct analgesic effects in animal studies independent of growth hormone release. This activity is attributed to selective interaction with opioid receptors involved in pain modulation, suggesting relevance for studying targeted analgesic pathways.

GHRP-2 has shown favorable safety and bioavailability profiles in animal research. Human dosing equivalence has not been established. All GHRP-2 products referenced are intended exclusively for laboratory research and educational purposes and are not approved for human consumption. Distribution is limited to licensed research entities.

Article Author

This article was researched and compiled by Dr. Logan, M.D., a physician-scientist trained at Case Western Reserve University School of Medicine with a background in molecular biology.

Scientific Researcher Acknowledgment

Jean-Alain Fehrentz, Ph.D., is a senior researcher in peptide chemistry and receptor pharmacology with academic and industrial experience across leading French research institutions. His extensive publication record has significantly contributed to ghrelin receptor ligand development.

Mention of Dr. Fehrentz is solely for academic acknowledgment. No endorsement or commercial affiliation is implied.

Referenced Citations

1. R. Hu et al., "Effects of GHRP-2 and Cysteamine Administration on Growth Performance, Somatotropic Axis Hormone and Muscle Protein Deposition in Yaks (Bos grunniens) with Growth Retardation," PloS One, vol. 11, no. 2, p. e0149461, 2016.
2. D. Yamamoto et al., "GHRP-2, a GHS-R agonist, directly acts on myocytes to attenuate the dexamethasone-induced expressions of muscle-specific ubiquitin ligases, Atrogin-1 and MuRF1," Life Sci., vol. 82, no. 9–10, pp. 460–466, Feb. 2008.
3. L. T. Phung et al., "The effects of growth hormone-releasing peptide-2 (GHRP-2) on the release of growth hormone and growth performance in swine," Domest. Anim. Endocrinol., vol. 18, no. 3, pp. 279–291, Apr. 2000.
4. B. Laferrère, C. Abraham, C. D. Russell, and C. Y. Bowers, "Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men," J. Clin. Endocrinol. Metab., vol. 90, no. 2, pp. 611–614, Feb. 2005.
5. B. Laferrère, A. B. Hart, and C. Y. Bowers, "Obese subjects respond to the stimulatory effect of the ghrelin agonist growth hormone-releasing peptide-2 on food intake," Obes. Silver Spring Md, vol. 14, no. 6, pp. 1056–1063, Jun. 2006.
6. G. Muccioli et al., "Growth hormone-releasing peptides and the cardiovascular system," Ann. Endocrinol., vol. 61, no. 1, pp. 27–31, Feb. 2000.
7. V. Bodart et al., "Identification and characterization of a new growth hormone-releasing peptide receptor in the heart," Circ. Res., vol. 85, no. 9, pp. 796–802, Oct. 1999.
8. D. D. Taub, W. J. Murphy, and D. L. Longo, "Rejuvenation of the aging thymus: growth hormone-mediated and ghrelin-mediated signaling pathways," Curr. Opin. Pharmacol., vol. 10, no. 4, pp. 408–424, Aug. 2010.
9. G. Gopinadh et al., "Prolonged oral treatment with MK-677, a novel growth hormone secretagogue, improves sleep quality in man," Neuroendocrinology, vol. 66, no. 4, pp. 278–286, Oct. 1997.
10. P. Zeng et al., "Ghrelin receptor agonist, GHRP-2, produces antinociceptive effects at the supraspinal level via the opioid receptor in mice," Peptides, vol. 55, pp. 103–109, May 2014.
11. Moulin, A. , Ryan, J. , Martinez, J. and Fehrentz, J. (2007), Recent Developments in Ghrelin Receptor Ligands. ChemMedChem, 2: 1242-1259.