MGF 2MG (Mechano Growth Factor)

MGF is produced from the IGF-I gene through alternative splicing and features distinct 3' exons compared to the liver or systemic type (IGF-IEa). In humans, it contains a 49 base pair insert, while rodents have a 52 base pair insert within the E domain of exon 5. This insertion leads to a reading frame shift, resulting in a different carboxy terminal sequence than that of systemic IGF-IEa. Both MGF and the other IGF isoforms share the same 5' exons that encode the IGF-I ligand-binding domain. The processing of the pro-peptide generates a mature peptide that contributes to the enhancement of protein synthesis. Furthermore, evidence suggests that the carboxy-terminal of the MGF peptide acts as an independent growth factor, which stimulates the proliferation of mononucleated myoblasts or satellite (stem) cells, consequently increasing their availability for local repair.

It appears that MGF serves a dual purpose; similar to other IGF-I isoforms, it promotes protein synthesis and activates satellite cells. However, the latter function of MGF is likely more significant since most mature IGF-I will originate from IGF-IEa during the second phase of repair. Nonetheless, research has demonstrated that MGF is a powerful inducer of muscle hypertrophy, as evidenced by experiments where MGF cDNA was inserted into a plasmid vector and introduced via intramuscular injection. This led to a 20% increase in the weight of the injected muscle within two weeks, with analyses revealing that this growth was due to an increase in muscle fiber size. Other studies using a viral construct with the liver type of IGF-I reported a 25% gain in muscle mass, although this effect took over four months to manifest (Musaro et al. 2001). Thus, MGF's dual role in activating satellite cells and promoting protein synthesis indicates it is significantly more effective than the liver type or IGF-IEa for facilitating rapid hypertrophy.

The peptide is typically administered at a dosage of 200-400 mcg per day and works synergistically with other compounds such as IGF and PEG.