MGF, also known as IGF-1Ec, is a variant of the systemic IGF-1 produced by the liver. Unlike systemic IGF-1, MGF is expressed specifically in response to muscle damage and is involved in repairing and adapting the muscle. It is expressed as a pulse after muscle damage and helps activate muscle stem cells to repair the muscle and contribute to growth. MGF and IGF-1 have similar functions in repairing and growing new cells. In order to have a longer effect, MGF must be PEGylated as its natural half-life is only minutes. Studies have shown that there is a differential expression of IGF-1 isoforms in response to exercise-induced muscle damage, with a rapid increase in MGF expression followed by a prolonged increase in IGF-1Ea and IGF-1Eb. Research has also shown that the action of synthetic MGF differs from that of mature IGF-1 and has its own unique effects on muscle cells. These findings suggest that MGF and IGF-1 may act as separate agents in muscle regeneration
- Philippou, Anastassios & Papageorgiou, E & Bogdanis, Gregory & Halapas, Antonios & Sourla, A & Maridaki, Maria & Pissimissis, Nikolas & Koutsilieris, Michael. (2009). Expression of IGF-1 Isoforms after Exercise-induced Muscle Damage in Humans: Characterization of the MGF E Peptide Actions In Vitro. In vivo (Athens, Greece). 23. 567-75.