AOD9604 (hGH Fragment 176-191): Structure, Lipolysis Research, and Scientific Literature
Origins and Development
AOD9604 is a synthetic modified fragment of human growth hormone corresponding to residues 176-191 of the full 191-amino acid hGH polypeptide. It was developed in the late 1990s by Professor Frank Ng and colleagues at Monash University in Melbourne, Australia. The rationale for its development was based on the observation that the C-terminal region of hGH appeared to be responsible for the lipolytic (fat metabolism) activity of the parent hormone, while the N-terminal region mediated the growth-promoting and diabetogenic effects.
By isolating and modifying this specific fragment, researchers aimed to create a tool compound that could be used to study fat metabolism signaling pathways independently of growth-promoting or insulin-antagonistic pathways.
Chemical Structure
AOD9604 consists of 16 amino acids corresponding to hGH residues 176-191 (Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe) with a key modification: the tyrosine residue at position 176 is acetylated, and the two cysteine residues (positions 182 and 189) form an intramolecular disulfide bond creating a cyclic structure in the C-terminal region. The molecular weight is approximately 1,817 Da.
The disulfide bond is critical for maintaining the three-dimensional conformation necessary for biological activity in assay systems.
Published Research
Lipid Metabolism Studies
The foundational research by Ng and colleagues at Monash University demonstrated that hGH fragment 176-191 stimulated lipolysis (triglyceride hydrolysis) in adipose tissue explants in vitro while showing no effect on IGF-1 levels or glucose homeostasis markers in preclinical models.
Adipocyte Studies
In vitro studies using 3T3-L1 preadipocyte cell lines demonstrated that AOD9604 enhanced both lipolysis (fat breakdown) and inhibited lipogenesis (de novo fatty acid synthesis) in a dose-dependent manner. The mechanism appears to involve β3-adrenergic receptor-independent pathways distinct from catecholamine-mediated lipolysis.
Cartilage and Chondrocyte Research
More recent in vitro studies have investigated AOD9604 in chondrocyte culture models, examining its effects on proteoglycan synthesis and cartilage matrix components. This represents an expanding area of research interest for the compound.
Regulatory History
AOD9604 received Generally Recognized As Safe (GRAS) status from the U.S. FDA in 2014 as a food ingredient, reflecting its favorable safety profile established in toxicological studies. This regulatory classification is notable in the peptide research space.
Future Research Directions
Current areas of investigation include further characterization of the specific receptor or binding target for AOD9604 (no definitive primary receptor has been confirmed), chondrocyte biology applications, and comparative studies with the full-length hGH fragment to elucidate the structural determinants of lipolytic versus growth-promoting activity.
Available at Crush Research: AOD9604 5mg vials. Every lot independently tested with published Certificate of Analysis.
All products are intended for in vitro and laboratory research use only. Not for human or veterinary use.