What is MGF (Mechano Growth Factor)?
Summary
MGF is an IGF-1 splice variant that increases in tissues after mechanical stress to 'activate' regeneration by expanding local stem/progenitor cells, especially in muscles. In humans, MGF (IGF-1Ec) increases within hours after resistance exercise — an effect that diminishes with aging.
Substance Properties
What is MGF?
MGF (Mechano Growth Factor) is a locally acting splice variant of the IGF-1 gene (human IGF-1Ec; rodent IGF-1Eb) upregulated after mechanical stress and tissue injury. It helps initiate repair by activating resident stem/progenitor cells — mainly muscle satellite cells — and shows tissue-specific roles in skeletal muscle, heart, and brain in preclinical models.
Role in muscle regeneration
After resistance exercise, MGF is rapidly expressed in skeletal muscles — within hours — before being replaced by the systemic IGF-1Ea form. This early mechanically-induced expression 'activates' dormant satellite cells, initiating muscle repair. With aging, the MGF response is significantly blunted.
MGF vs. IGF-1 LR3
While IGF-1 LR3 is a long-acting IGF-1 variant that circulates systemically, MGF acts locally and short-term. MGF activates progenitor cells, while IGF-1 LR3 promotes differentiation and growth. These two factors act complementarily in different phases of regeneration.
Roles beyond muscles: Heart and brain
Beyond skeletal muscles, MGF is studied for cardioprotective properties after infarction (cardiac stem cell activation) and neuroprotective properties in models of ischemic brain injury. Data remains exclusively preclinical.
Related Guides
Frequently Asked Questions (FAQ)
Does MGF require PEGylation?
The PEGylated form (PEG-MGF) has a longer half-life, which may be useful in certain research protocols. The natural form degrades rapidly in vivo.
Does MGF increase muscle mass?
In animal models, MGF promotes satellite cell activation, but results in humans have not been clinically documented.
References & Studies
- Hill M, Goldspink G. Expression and splicing of the insulin-like growth factor gene in rodent muscle is associated with muscle satellite (stem) cell activation following local tissue damage. J Physiol. 2003;549(Pt 2):409-418.
- Goldspink G. Mechanical signals, IGF-I gene splicing, and muscle adaptation. Physiology. 2005;20:232-238.
Disclaimer
This article is exclusively educational for researchers. It does not constitute medical advice.
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