What Variants of MGF Are There & How Do They Differ in Their Action?

The mechano-growth factor, or MGF, is an essential protein found in human tissues. It is an variant of another human protein, the insulin-like growth factor 1, or IGF-1. MGF also has a small variant, the E-peptide, that consists only of the C-terminal end of the MGF protein. All three of these proteins, the MGF, IGF-1 and E-peptide, have very similar actions in the body.

IGF-1

• During the early post-natal development, IGF-1 is produced by your liver and it plays a role in growth together with the growth hormone. Later in your life, IGF-1 functions in maintaining your body tissues and the well-being of your entire body. The production of IGF-1 declines as you age, which seems to have a role in muscle-mass decrease, or atrophy. Research done with animal models indicates that when IGF-1 production is increased in the muscle tissue, it seems to increase muscle mass, or hypertrophy, according to a study published in the biochemistry journal “FEBS Letters” in 2001. In addition, IGF-1 may also promote nerve cell regeneration, according to a study published in the “Journal of Cerebral Blood Flow and Metabolism” in 2009.

MGF Variants

• The MGF is encoded by the same gene that encodes the IGF-1, and thus, it is also known as the IGF-1Ec variant in humans. The MGF, like all protein molecules, contain an N- and C-terminal end. The C-terminal portion of the MGF molecule, also known as the E-peptide, can function independently from the rest of the MGF molecule and seems to exhibit the same protective qualities as the whole MGF molecule.

MGF Function

• The MGF increases muscle cell proliferation, a process during which the muscle cell number increases through cell division. MGF production is reduced in the muscle tissue of the elderly and may be associated with muscle dystrophy. As a result, increasing MGF production in the muscle could have a regenerative function and could be a potential therapeutic agent for muscle repair and muscle growth, according to a study published in the journal "Protein Expression and Purification" in 2008. Besides having a role in muscle regeneration, a study published in the “FASEB Journal” in 2005 found that MGF production was increased after brain ischemia in ischemia-resistant hippocampal neurons in gerbils. These results indicate that the MGF molecule may also have a neuroprotective function against brain ischemia.

MGF E-Peptide

• The E-peptide seems to have similar actions to the whole MGF protein. A study published in “FEBS Letters” in 2007 showed that the E-peptide increases cell proliferation in healthy muscle tissue as well as in diseased muscle tissue. The study also showed that E-peptide increases the stem-cell pool in muscle tissue and, thus, may facilitate muscle repair. The E-peptide may also have neuroprotective qualities, like the whole MGF protein, according to the “FASEB Journal” study. The study found that the E-peptide helped protect neurons against damage in a gerbil model of brain ischemia. Since the E-peptide can be synthesized in the laboratory using molecular cloning techniques, it may have a more promising role as a therapeutic agent than the larger MGF or IGF-1 proteins.