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TwisT
12-26-2010, 04:50 PM
MGF


After resistance exercise, IGF-1 is released within the muscle. Specifically, at this time, immediately following the mechanical use of a muscle, the IGF-I gene is spliced towards MGF which initiates hypertrophy and repair of local muscle damage. It does so both by activating muscle stem cells and satellite cells, but also via various other anabolic processes. (1) It differs from “regular” IGF-1 mainly due to it’s C-Terminal sequence.

Background
At the time of this writing, bodybuilders and athletes have been experimenting with MGF for a couple of years already. It was first discovered in the muscle by Goldspink, et al. In human muscle, a 49-base insert changes the reading frame in mechano growth factor (MGF) as compared to IGF-1.

http://www.mesomorphosis.com/images/steroid-structure/mgf-chart.gif

Action
When mechanical overload is introduced to a muscle (as by weight training), the IGF-1 gene released and is differentially spliced during the bodies response. Initially, it it is spliced to produce predominantly IGF-1Ec (called the MGF splice variant of IGF-1). This early splicing stimulates satellite cells into activation. Which in turn allows the activation of extra undamaged nuclei to grow new muscle fiber and tissue. The appearance of MGF also initiates the upregulation of new protein synthesis. After this initial splicing of IGF-1 into MGF, production then switches towards producing a systemic release of IGF-1Ea from the liver, which also upregulates protein synthesis as well. The expression of IGF-1 splice variants, over the course of the healing and regrowth phase of muscle repair is thought to be the primary anabolic mechanism by which the body produces new muscle. MGF is available as an injectable peptide, and it has been anecdotally shown that injecting it will cause a response in the area resulting in localized muscle growth.

http://www.mesomorphosis.com/images/steroid-structure/mgf-diagram.gif
Technical Data
In a rodent study, a single intramuscular injection into muscle resulted in a 25% increase in mean muscle fibre cross section area within three weeks.(2) Using a similar protocol, liver-derived IGF-1 took four months to produce a 15% increase.(3) It would also appear that with regards to age, the young have a better ability to respond to MGF (4), and that the elderly experience a decreased response to MGF which results in a decreased ability to stimulate the growth of new muscle tissue. In the words of the man known as the father of MGF research: “MGF is… a prime candidate for gene doping for enhancement of athletic performance.”(1)

User Notes
I’ve personally used MGF several times and think it’s a really great product. Admittedly, I have only used it in conjunction with Lr3IGF-1, but many (myself included) feel that there’s probably quite a bit of synergy to be found between these two peptides. I experienced muscle growth (localized) with MGF, but not really much of a strength increase over what I would have experienced with just the IGF. Most users find MGF to be very good for muscle growth and typically use a protocol of 100mcgs injected into each lagging muscle just after working it. A further discussion of how to incorporate this compound can be found in my article “Peptides: The next frontier in hypertrophy”




by Anthony Roberts

References


British Journal of Sports Medicine 2005;39:787-788; doi:10.1136/bjsm.2004.015826 © 2005 by BMJ Publishing Group Ltd & British Association of Sport and Exercise Medicine
Goldspink G, Yang SY. Method of treating muscular disorders. United States Patent. Patent No US 6,221,842 B1, Apr 24 2001.
Barton-Davis E, Shoturma DI, Musaro A, et al. Viral mediated expression of insulin-like growth factor-I blocks the aging-related loss of skeletal muscle function. Proc Natl Acad Sci USA 1998;95:15603–7
J Physiol (2003), 547.1, pp. 247-254© Copyright 2003 The Physiological SocietyDOI: 10.1113/jphysiol.2002.0321362010
©2010 MESO-Rx "Mechano Growth Factor" (steroid-profiles/mechano-growth-factor.htm)

TwisT
12-26-2010, 05:03 PM
Mechano-growth factor, an IGF-I splice variant, rescues motoneurons and improves muscle function in SOD1(G93A) mice.

Riddoch-Contreras J (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Riddoch-Contreras%20J%22%5BAuthor%5D), Yang SY (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Yang%20SY%22%5BAuthor%5D), Dick JR (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Dick%20JR%22%5BAuthor%5D), Goldspink G (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Goldspink%20G%22%5BAuthor%5D), Orrell RW (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Orrell%20RW%22%5BAuthor%5D), Greensmith L (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Greensmith%20L%22%5BAuthor%5D).
Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, UCL, Queen Square, London WC1N 3BG, UK.

Abstract

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by motoneuron degeneration. Although viral delivery of IGF-I has shown therapeutic efficacy in the SOD1(G93A) mouse model of ALS, clinical trials of IGF-I in ALS patients have led to conflicting results. Here we examine the effects of an IGF-I splice variant, mechano-growth factor (MGF) which has previously been shown to have greater neuroprotective effects than IGF-I in a number of models of neurodegeneration. A mammalian expression plasmid containing either MGF or, for comparison, the IGF-I cDNA sequence was delivered to the hindlimb muscles of SOD1(G93A) mice at 70 days of age, at symptom onset. Treatment with either IGF-I or MGF resulted in a significant improvement in hindlimb muscle strength, and an increase in motor unit and motoneuron survival. Significantly more motoneurons survived in MGF treated mice.

PMID: 19038252 [PubMed - indexed for MEDLINE]

TwisT
12-26-2010, 05:04 PM
Growth hormone stimulates mechano growth factor expression and activates myoblast transformation in C2C12 cells.

Imanaka M (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Imanaka%20M%22%5BAuthor%5D), Iida K (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Iida%20K%22%5BAuthor%5D), Murawaki A (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Murawaki%20A%22%5BAuthor%5D), Nishizawa H (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Nishizawa%20H%22%5BAuthor%5D), Fukuoka H (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Fukuoka%20H%22%5BAuthor%5D), Takeno R (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Takeno%20R%22%5BAuthor%5D), Takahashi Y (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Takahashi%20Y%22%5BAuthor%5D), Okimura Y (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Okimura%20Y%22%5BAuthor%5D), Kaji H (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Kaji%20H%22%5BAuthor%5D), Chihara K (http://www.ncbi.nlm.nih.gov/pubmed?term=%22Chihara%20K%22%5BAuthor%5D).
Division of Diabetes, Metabolism, and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Abstract

Mechano growth factor (MGF) is an alternatively spliced variant of insulin-like growth factor-I (IGF-I). Previous reports have revealed that the MGF in skeletal muscles is induced by mechanical overload or muscle injury. In the present study, we examined the effect of growth hormone (GH) on MGF expression in C2C12 mouse muscle cell lines since GH is the principal regulator of IGF-I. The MGF mRNA increased 1 h following GH stimulation whereas IGF-IEa mRNA, which encodes a systemic type of IGF-I, increased 4 h following GH stimulation. The diverse expression of MGF and IGF-IEa was also observed in the case of muscle injury by using bupivacaine in the same cell line. Furthermore, GH induced the increase of MyoD as well as M-cadherin expression, the peak of which was parallel to that of MGF. These results indicate that GH directly and preferentially increased MGF prior to the IGF-IEa expression in C2C12 cells, which may lead to the activation of muscle satellite cells.

PMID: 18772608 [PubMed - indexed for MEDLINE]