What is AOD-9604?
AOD-9604 is a fragment analogue rather than a full length hormone. It reproduces the carboxy terminal region of the growth hormone sequence with an added tyrosine at the amino terminus, and the molecular reference for this catalog lists the formula C78H123N23O23S2 with an average mass of 1815.08. Two sulfur atoms appear in that formula, consistent with the cysteine pair that closes the small disulfide loop characteristic of this region. No residue sequence is recorded in the reference, so none is reproduced here.
The literature interest in this fragment is that it separates the metabolic region of growth hormone from the region responsible for receptor mediated growth signalling. In adipocyte cell models and rodent studies it has been examined for effects on lipolytic markers and lipogenic enzyme activity without measurable stimulation of insulin-like growth factor 1 in the animals studied (Heffernan, 2001).
Much remains unresolved. No high affinity receptor for the fragment has been convincingly identified, reported effects vary between adipose depots and between species, and several groups have failed to reproduce lipolytic readouts in isolated adipocyte preparations.
Reconstitution & handling
Bacteriostatic or sterile water is added gently down the vial wall and the vial is swirled rather than shaken until the cake clears. Small disulfide containing peptides dissolve readily but are sensitive to strongly alkaline diluents, which promote disulfide scrambling, so neutral water is the usual choice. Concentration is arithmetic, so 2 mL added to a 5 mg vial produces 2.5 mg per millilitre.
Storage & stability
Lyophilized vials are stored at -20 °C, protected from light and moisture, and equilibrated to room temperature before the stopper is pierced. Reconstituted material is refrigerated at 2 to 8 °C and aliquoted into single use volumes to avoid repeated freezing and thawing. Because the molecule carries a disulfide bond, reducing agents and warm alkaline conditions are avoided, since both open the loop and change the chromatographic profile.
How it's tested
Each lot is assayed by reversed phase HPLC at 214 and 220 nm and reported at 99 percent or greater main peak area. Mass spectrometry confirms identity against the theoretical average mass of 1815.08 derived from C78H123N23O23S2, which also separates the closed disulfide form from the reduced open chain, since the two differ by two mass units. A lot-matched certificate is available on request.