GHRP-2¶
GHRP-2 (Growth Hormone Releasing Peptide-2, CAS 158861-67-7) is a synthetic hexapeptide ghrelin receptor (GHS-R1a) agonist with a molecular weight of approximately 817.0 Da and formula C₄₅H₅₅N₉O₆. As one of the most potent growth hormone secretagogue peptides, GHRP-2 is a core research tool for studying ghrelin receptor-mediated GH release, appetite signaling, and the hypothalamic-pituitary-somatotropic axis.
Technical Specifications¶
| Property | Value |
|---|---|
| CAS Number | 158861-67-7 |
| Molecular Formula | C₄₅H₅₅N₉O₆ |
| Molecular Weight | ~817.0 Da |
| Purity | ≥99% (HPLC-verified) |
| Appearance | Lyophilized white powder |
| Solubility | Soluble in sterile water and aqueous buffers |
| Storage | -20°C (lyophilized), 2–8°C (reconstituted) |
Mechanism of Action¶
GHRP-2 binds as a full agonist at the growth hormone secretagogue receptor type 1a (GHS-R1a, the ghrelin receptor), a Gαq-coupled GPCR expressed in the arcuate nucleus of the hypothalamus and on pituitary somatotrophs. Unlike GHRH analogs that signal through Gαs/cAMP, GHRP-2 activates phospholipase C (PLC) via Gαq, generating inositol trisphosphate (IP₃) and diacylglycerol (DAG), which mobilize intracellular calcium and activate protein kinase C (PKC). This calcium-dependent pathway directly stimulates GH vesicle exocytosis from somatotrophs while simultaneously inhibiting somatostatinergic tone from hypothalamic periventricular neurons. GHRP-2 also activates hypothalamic neuropeptide Y (NPY) and agouti-related peptide (AgRP) neurons via GHS-R1a, which contributes to appetite stimulation. When co-administered with GHRH analogs, GHRP-2 produces a synergistic GH response because the GHRH receptor (Gαs) and GHS-R1a (Gαq) activate complementary, non-redundant signaling pathways.
Research Applications¶
- Primary: Ghrelin receptor (GHS-R1a) pharmacology — Gαq/PLC signaling, GH secretion
- Secondary: Appetite regulation and energy homeostasis, hypothalamic NPY/AgRP neuron activity studies, combination GH secretagogue protocols
- Model Systems: In vitro (GHS-R1a-transfected cell lines, primary pituitary cell cultures), in vivo (GH release profiling in rodents, feeding behavior studies)
Quality Control & Analytical Methods¶
- HPLC: ≥99% purity verification at 214/220 nm (C18 reversed-phase column)
- Mass Spectrometry: ESI-MS for molecular weight confirmation (~817.0 ±1.0 Da)
- Peptide Content: Amino acid analysis (AAA) for net peptide content determination
- Endotoxin: <1 EU/mg (LAL assay)
- TFA Content: <1% (ion chromatography)
Stability & Storage¶
| Condition | Stability |
|---|---|
| -20°C (lyophilized) | 24 months |
| 4°C (lyophilized) | 6 months |
| 25°C (lyophilized) | 1 month |
| Reconstituted (4°C) | 7 days |
| Reconstituted (-20°C) | 30 days |
Key Research References¶
- Bowers et al. (1990) — Discovery and characterization of GHRP-2, a novel synthetic hexapeptide with potent GH-releasing activity. Endocrinology. PMID: 2164920
- Kojima & Kangawa (2005) — Ghrelin: structure and function. Physiol Rev. PMID: 15788705
- Nass et al. (2008) — The ghrelin receptor agonist GHRP-2: pharmacological characterization. Pharmacol Ther. PMID: 18692531
Source & Purchase¶
For researchers requiring research-grade GHRP 2 with full analytical documentation including HPLC, LC-MS, and Certificate of Analysis, visit the HK Peptides product page for specifications, bulk pricing, and ordering.
Related Molecules¶
- GHRP-6 — Ghrelin receptor agonist with appetite effects
- CJC-1295 (no DAC) — GHRH analog, complementary mechanism
- Ipamorelin (in blends) — Selective GHS-R1a agonist
- All Product Specifications
FAQ¶
Q: What purity level is standard for GHRP-2? A: HK Peptides supplies GHRP-2 at ≥99% purity by HPLC with full COA documentation.
Q: How should GHRP-2 be stored for research use? A: Lyophilized GHRP-2 should be stored at -20°C. Reconstituted solutions at 4°C for short-term use (up to 7 days).