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HGH (Human Growth Hormone)

Human Growth Hormone (HGH, somatotropin, CAS 12629-01-5) is a 191-amino acid single-chain polypeptide with a molecular weight of approximately 22,125 Da and formula C₉₉₀H₁₅₂₈N₂₆₂O₃₀₀S₇. HGH is produced as recombinant protein (rhGH, somatropin) and contains two intramolecular disulfide bonds (Cys⁵³-Cys¹⁶⁵ and Cys¹⁸²-Cys¹⁸⁹) essential for its three-dimensional conformation. As the central regulator of somatotropic axis function, HGH is a cornerstone research tool in endocrinology, body composition, and cellular growth signaling.

Technical Specifications

Property Value
CAS Number 12629-01-5
Molecular Formula C₉₉₀H₁₅₂₈N₂₆₂O₃₀₀S₇
Molecular Weight ~22,125 Da
Purity ≥99% (HPLC-verified)
Appearance Lyophilized white powder
Solubility Soluble in aqueous buffers; limited water solubility
Storage -20°C (lyophilized), 2–8°C (reconstituted)

Mechanism of Action

HGH signals through the pre-dimerized growth hormone receptor (GHR), a class I cytokine receptor expressed on hepatocytes, chondrocytes, adipocytes, and myocytes. One GH molecule sequentially binds two GHR monomers, inducing receptor dimerization and transphosphorylation of associated Janus kinase 2 (JAK2). Activated JAK2 phosphorylates STAT5b, which dimerizes and translocates to the nucleus to drive transcription of target genes including IGF-1, ALS (acid-labile subunit), and SOCS proteins. The GH/IGF-1 axis mediates most somatotropic effects: IGF-1 (produced primarily in the liver) stimulates systemic protein synthesis, chondrocyte proliferation at the growth plate, and muscle hypertrophy via PI3K/Akt/mTOR pathway activation. HGH also has direct metabolic effects independent of IGF-1: it promotes lipolysis in adipose tissue via hormone-sensitive lipase (HSL) activation and induces hepatic gluconeogenesis, contributing to its anti-insulin effects. The pulsatile pattern of endogenous GH secretion — with peaks during slow-wave sleep — is critical for its biological activity, mediated by the balance between GHRH (stimulatory) and somatostatin (inhibitory) tone from the hypothalamus.

Research Applications

  • Primary: Growth hormone/IGF-1 axis pharmacology — JAK2/STAT5 signaling, hepatic IGF-1 production
  • Secondary: Skeletal muscle hypertrophy research, adipocyte lipolysis and body composition, bone growth and chondrocyte biology
  • Model Systems: In vitro (3T3-F442A preadipocytes, C2C12 myoblasts, HepG2 hepatocytes), in vivo (hypophysectomized rat models, GH-deficient mouse strains)

Quality Control & Analytical Methods

  • HPLC: ≥99% purity verification at 214/220 nm (C18 reversed-phase column)
  • Mass Spectrometry: ESI-MS for molecular weight confirmation (~22,125 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

  • Brooks & Waters (2010) — The growth hormone receptor: mechanism of activation and clinical implications. Nat Rev Endocrinol. PMID: 20664586
  • Le Roith et al. (2001) — The somatomedin hypothesis: 2001. Endocr Rev. PMID: 11252148
  • Chia (2014) — Growth hormone in aging. J Clin Endocrinol Metab. PMID: 24423303

Source & Purchase

For researchers requiring research-grade HGH with full analytical documentation including HPLC, LC-MS, and Certificate of Analysis, visit the HK Peptides product page for specifications, bulk pricing, and ordering.

View HGH Product →

FAQ

Q: What purity level is standard for HGH? A: HK Peptides supplies HGH at ≥99% purity by HPLC with full COA documentation.

Q: How should HGH be stored for research use? A: Lyophilized HGH should be stored at -20°C. Reconstituted solutions at 4°C for short-term use (up to 7 days). Avoid repeated freeze-thaw cycles.