Somatotropin (176-191)
[CAS# 66004-57-7]

Identification

• Classification: Biological >> Proteins and peptides >> Hormone
• Name: Somatotropin (176-191)
• Synonyms: HGH FRAG 176-191; [(2S)-2-[[(2S,3S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-amino-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-5-carbamimidamidopentanoyl]amino]-3-methylpentanoyl]amino]-3-methylbutanoyl] (4S)-5-[[2-[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-hydroxypropanoyl]amino]-3-sulfanylpropanoyl]amino]acetyl]amino]-3-phenylpropanoyl]oxy-2-oxoethyl]amino]-4-[[(2S)-2-[[(2S)-2-[[(2S)-5-carbamimidamido-2-[[(2R)-2-[[(2S)-2,5-diamino-5-oxopentanoyl]amino]-3-sulfanylidenepropanoyl]amino]pentanoyl]amino]-3-hydroxypropanoyl]amino]-3-methylbutanoyl]amino]-5-oxopentanoate
• Molecular Formula: C₇₈H₁₂₃N₂₃O₂₂S₂
• Molecular Weight: 1799.08
• CAS Registry Number: 66004-57-7
• SMILES: CC[C@H](C)[C@@H](C(=O)N[C@@H](C(C)C)C(=O)OC(=O)CC[C@@H](C(=O)NCC(=O)OC(=O)[C@H](CC1=CC=CC=C1)NC(=O)CNC(=O)[C@H](CS)NC(=O)[C@H](CO)N)NC(=O)[C@H](C(C)C)NC(=O)[C@H](CO)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](C=S)NC(=O)[C@H](CCC(=O)N)N)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CC2=CC=CC=C2)N

Properties

• Density: 1.5±0.1 g/cm³ Calc.^*
• Index of refraction: 1.651 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Discovory and Applicatios

Somatotropin (176‑191) is a synthetic peptide fragment derived from the C-terminal region of human growth hormone, consisting of amino acids 176 through 191. This fragment retains some of the lipolytic activity of full-length growth hormone but is substantially smaller and more stable, which makes it of interest for research and potential therapeutic applications related to fat metabolism and body composition.

The development of somatotropin (176‑191) emerged from studies on the structure-function relationship of human growth hormone. Researchers identified that the C-terminal region, encompassing residues 176 to 191, is responsible for stimulating lipolysis in adipose tissue. This observation led to the design of a peptide that selectively mimics this lipolytic function without significantly affecting growth-promoting activity, allowing for targeted applications in metabolic regulation.

Pharmacologically, somatotropin (176‑191) binds to specific receptors on adipocytes, activating intracellular signaling pathways that enhance the breakdown of triglycerides into free fatty acids and glycerol. This selective lipolytic effect does not appear to produce the same degree of systemic growth-promoting effects observed with full-length growth hormone, which is beneficial in minimizing potential side effects.

In research settings, somatotropin (176‑191) has been investigated for its effects on fat reduction, body composition improvement, and metabolic health. Preclinical studies suggest that administration of this peptide can reduce adiposity, particularly in visceral fat deposits, and may improve lipid profiles. Its effects on lean body mass appear to be limited compared to full-length growth hormone, which highlights its role as a targeted metabolic modulator rather than a general anabolic agent.

Due to its peptide nature, somatotropin (176‑191) is administered parenterally, typically via subcutaneous injection. The peptide is relatively small and exhibits greater stability than full-length growth hormone, but it is still susceptible to enzymatic degradation, necessitating careful formulation and storage. Stability can be enhanced by lyophilization and storage at low temperatures.

Although primarily studied in laboratory and preclinical models, somatotropin (176‑191) has generated interest in the context of obesity, metabolic syndrome, and age-related changes in body composition. Its selective activity provides a foundation for the development of therapeutic agents that target fat metabolism without affecting overall growth or endocrine balance. Ongoing research continues to investigate its mechanisms of action, optimal dosing regimens, and potential clinical applications.

Overall, somatotropin (176‑191) represents a functionally significant fragment of human growth hormone with targeted lipolytic activity. Its discovery and characterization have advanced the understanding of structure-function relationships in peptide hormones and offer potential avenues for therapeutic intervention in metabolic disorders.

References

Ng FM, Bornstein J (1978) Hyperglycemic action of synthetic C‑terminal fragments of human growth hormone. American Journal of Physiology 234(5) E521–E526 DOI: 10.1152/ajpendo.1978.234.5.E521