Loss of muscle mass in old age and in certain diseases is associated
with an impaired ability to express MGF.
- The ability to produce MGF declines with age, and this is commensurate
with the decline in circulating GH levels.
- MGF has been shown to boost muscle mass by improving the ability
of wasted tissue to grow.
- MGF has been shown to improve the ability of wasted tissue to
grow.
- MGF has been shown to activate muscle stem cells.
- MGF has been shown to increase the upregulation of protein synthesis.
- MGF induces rapid muscle hypertrophy.
- MGF has considerable potential as a generic means of treating
muscle cachexia.
- Mechano Growth Factor (MGF) targets skeletal tissue, and promotes
muscle growth by repairing the damaged tissue and upregulating
protein synthesis.
The sequencing of the human genome showed that there are only
about 40,000 genes. However, there are many more proteins. This
is because some genes are spliced to produce different protein/peptides
which usually have different biological functions. Combining physiological
and molecular biology methods made it possible to identify and
characterize a local muscle growth/repair factor (MGF). After
resistance exercise, the IGF-I gene is spliced towards MGF which
?kick starts? hypertrophy and repair of local muscle damage by
activating the muscle stem cells as well as anabolic processes.
Interestingly, loss of muscle mass in old age and in certain diseases
is associated with an impaired ability to express MGF.
Mechano Growth Factor (MGF) also known
as IGF-1Ec is a growth factor/repair factor that is derived from
exercised or damaged muscle tissue. MGF has been shown to boost
muscle mass by improving the ability of wasted tissue to grow
and improve itself by activating muscle stem cells and increasing
the upregulation of protein synthesis. MGF is a part of the IGF
family, but, in the case of MGF, this part of the peptide acts
as a separate growth factor involved in initiating muscle satellite
(stem) cell activation in addition to its IGF-Ireceptor domain
which increases protein synthesis, and hence improves muscle mass.
(Adams GR 2002).
Mechano Growth Factor (MGF) is derived
from the insulin-like growth factor
(IGF-I) but its sequence differs from the systemic IGF-I produced
by the liver. MGF is expressed by mechanically overloaded muscle
and is involved in tissue repair and adaptation. It is expressed
as a pulse following muscle damage and is apparently involved
in the activation of muscle satellite (stem) cells. These donate
nuclei to the muscle fibers that are required for repair and for
the hypertrophy processes which may have similar regulatory mechanisms.
Hence, Mechano growth Factor (MGF) appears to be more anabolic
than IGF because MGF responds to the signals produced by damaged
muscle tissue induced by exercise and actually repairs the tissue
and prevents cell death.
Loss of muscle mass (sarcopenia) is one of the main problems
associated with ageing as it has major health care as well as
socioeconomic implications. The growth hormone (GH)/IGF-I axis
is regarded as an important regulator of muscle mass. However,
it is now appreciated that other tissues in addition to the liver
express IGF-I and that there are local as well as systemic forms
of IGF-I which have different functions.
At least two different kinds of IGF-I that are expressed by skeletal
muscle are derived from the IGF-I gene by alternative splicing,
one of which is expressed in response to physical activity which
has now been called ?mechano growth factor? (MGF). The other is
similar to the systemic or liver type (IGF-IEa) and is important
as the provider of mature IGF-I required for upregulating protein
synthesis.
MGF differs from systemic IGF-IEa in that it has a different
peptide sequence which is responsible for replenishing the satellite
(stem) cells in skeletal muscle, in other words it is more anabolic.
In vivo experiments in which muscles of the rat were subjected
to mechanical damage or injection of a myotoxic agent also demonstrated
(Hill &Goldspink, 2003) that MGF precedes muscle satellite
(stem) cell activation. This is in accord with the finding that
when skeletal muscle cells in culture, were either transfected
with the MGF cDNA or were treated with the MGF carboxy peptide
they increased in number but stayed as monocleated myoblasts (Yang
& Goldspink, 2002).
It appears that MGF plays a dual role in inducing satellite cell
activation as well as protein synthesis and this is probably why
it is much more potent than the liver type or IGF-IEa for inducing
rapid muscle hypertrophy.
The ability to produce MGF declines with age, and this is commensurate
with the decline in circulating GH levels. GH treatment up regulates
the level of IGF-I gene expression in older people and when combined
with resistance exercise more is spliced towards MGF and hence
should improve the ability of muscle to respond to physical activity.(Goldspink
and Harridge 2004).
The characterization of a local tissue repair
factor (mechano growth factor, MGF) that is produced by exercised
and/or damaged muscle by differential splicing of the IGF-I gene
provides understanding of how muscle is maintained in the young
normal individual. Mechano Growth Factor, or MGF, is different
to the systemic IGF-I as it has an insert of 49 base pairs in
exon 5 that introduces a reading frame shift resulting in a C
terminal peptide with unique properties.
Muscle is a post-mitotic tissue and as cell replacement is not
a means of tissue repair there has to be an efficient local repair
mechanism otherwise the damaged cells undergo cell death. The
extra nuclei for muscle repair and hypertrophy are provided by
the muscle satellite (stem) cells. The pool of these stem cells
is apparently replenished by the action of MGF, which is produced
as a pulse following a mechanical challenge. Unfortunately, the
production of MGF is deficient in certain diseases such as in
the muscular dystrophies in which the mechanotransduction mechanism,
which may involve the dystrophin complex, is defective. In elderly
muscles, decreased levels of growth hormone apparently mean that
there is less primary RNA transcript of the IGF-I gene to be spliced
towards MGF. Consequently, there is an increasing inability to
maintain muscle mass during ageing. Delivery of MGF and cDNA or
peptide produces marked increases in the strength of normal as
well as diseased muscle and, therefore, MGF has considerable potential
as a generic means of treating muscle cachexia. (Goldspink 2006).
Skeletal muscle is one of the few tissues with the capacity for
rapid and widespread repair. The source of this regenerative ability
lies in precursor stem-cell reserves that are harbored by the
myofibers. The myofibers (muscle fibers) that comprise skeletal
muscle are muscle cells packed with contractile machinery (myofibrils),
rechargeable energy sources (mitochondria), many nuclei (myonuclei),
and a cytoplasmic unit (sarcoplasm, over two-thirds of which is
water), each competing in a sense for space inside the cell. (Linstedt
SL 1998). Mechano Growth Factor targets skeletal tissue, and promotes
muscle growth by repairing the damaged tissue and upregulating
protein synthesis.
RESEARCH DOSAGE:
100-200mcg every day.
Peptide is best administered at least twice daily, bi-lateral
doses (so divide the research dose into two administrations on
your research subject) this will help to keep blood levels consistent
in your research subject, in cellular culture, or in vitro.
