Mechano Growth Factor
Mechano Growth Factor, a peptide. Alternative splice product of the IGF-1 gene expressed in response to mechanical stretch. The unique E-domain C-terminal 24-aa…
Alternative splice product of the IGF-1 gene expressed in response to mechanical stretch. The unique E-domain C-terminal 24-aa peptide (often called 'MGF') is proposed to activate satellite cells independently of the IGF-1R. Synthetic 24-mer is what's supplemented. No plasma half-life has ever been published for the E-domain peptide: the only sourced statement is qualitative, Goldspink 2001 (PMID:11915923) reporting that MGF "is not glycosylated, is smaller, and has a shorter half-life in the unbound state than the systemic liver type IGF-1". Local injection is the vendor rationale rather than a measured constraint.
PubChem has no entry for the PEGylated form. THE STRUCK NUMBER: this record's mechanism used to assert a plasma half-life under 10 minutes with no citation, and that number is not in the literature — `"mechano growth factor"[tiab] AND half-life` returns exactly one record, PMID:11915923, which is qualitative, and a further sweep of eleven MGF papers turned up no half-life sentence and no minute-scale value at all. Those eleven are deliberately NOT listed here: the sweep is a negative result reported by a search agent rather than something re-read value by value, and eleven bare identifiers in a note would read as a citation trail this record has not earned. PEG-MGF IS AN ALIAS, NOT A MOLECULE WITH ITS OWN DISPOSITION, on the evidence available: field-restricted searches (`"PEG-MGF"[tiab]`, `pegylated[tiab] AND "mechano growth factor"[tiab]`) return ONE record between them, PMID:42395176, a clinical-guidance review of grey-market performance products that names it in a bare parenthetical list and states no stability claim, no half-life, no species, no dose and no mechanism specific to the PEGylated form. MGF-Ct24E searches return nine records, none mentioning PEG. TWO TRAPS THAT WOULD PUT A HALF-LIFE ON THIS RECORD WRONGLY. PMID:28110155 reports a human half-life of 140-200 h for PEGylated rhIGF-I (RO5046013), which is FULL-LENGTH IGF-I and not the 24-residue E-domain peptide — almost certainly the origin of the vendor claim that PEG-MGF lasts days. And PMID:1281675 gives mouse half-lives for "recombinant mast cell growth factor (rMGF)", where MGF is SCF / kit ligand, a different protein sharing the abbreviation. Neither belongs here. What "stabilized" MGF means in the literature is biomaterials, never PEG: microencapsulation (PMID:24768406) and covalent grafting to modified poly(D,L-lactic acid) (PMID:22941771, PMID:23594073). Note also PMID:24253050, which failed to reproduce MGF activity at all and concludes that the results "call in to question whether there is a physiological role for MGF".
Sources: PMID:11915923, PMID:42395176, PMID:28110155