Myostatin
The transformation of bodybuilding has been amazing in recent years.
When comparing bodybuilders from earlier days with the bodybuilders
of the last decade we are amazed at the changes. What was once considered
huge is new considered mediocre. This change can be contributed
to a number of factors, including scientific nutrition, smarter
training, hormone manipulation and a better understanding of rest-recovery.
Recently a discovery has been made that could possibly take muscular
growth to a higher level.
In 1997 Mcpherron and Lee from John Hopkins University discovered
a gene that could be responsible for abnormal muscular growth in
cattle. It is called the myostatin gene (nickname "Schwarzenegger
Gene"). The gene produces a protein called myostatin that regulates
muscular growth. Experiments where the genes were mutated in Belgian
Blue and Piedmontse cattle led to increased muscularity. Gains of
up to 30% above normal levels of muscularity have been shown in
cattle that experienced myostatin mutations.
Shortly after the discovery of the myostatin gene in cattle the
gene was discovered in mice. Mutation of the gene in mice resulted
in 200-300% increases in muscle mass. The studies showed us that
myostatin had the same biological function in cattle and mice. These
discoveries led to further investigations of the myostatin gene.
Scientists have discovered the gene in other vertebra animals including
pigs, chickens, turkeys and humans.
Recent reports state that KFC is working on producing larger chickens
through myostatin mutation. Sources also say that McDonald's is
working on a supercow that is six times larger than normal cows.
These reports are purely speculation; they are not official at this
time.
Myostatin belongs to a family of molecules called transforming
growth factors beta (TGF-b ). It is also called( GDF-8 ) growth
and differentiation factor - 8. TGFb subtypes are based on their
related structures. GDF is one of these structures which specifically
regulates growth and differentiation. In the beginning researchers
thought myostatin was present only in skeletal muscle. Since then,
a New Zealand team of researchers detected myostatin in cardiac
muscle. Research at Purdue University detected the myostatin gene
in lactating mammary glands of pigs.
Myostatin plays a role in prenatal muscular growth. At this time
we have little knowledge of myostatins role in muscle regeneration.
The process of muscle regeneration is a complex situation. In young
animals hormones and growth factors are likely to induce growth.
As animals become adults these factors become down regulated. The
muscles ability to express protein synthesis is lessened.
MyoD, IGF-I and myogenin are factors in determining a muscle cells
specific characteristics. Muscle regulatory factor 4 ( MRF-4 ) mRNA
expression is the dominant factor in adult muscular growth. As you
can see in addition to myostatin there are other factors involved
in the regulation of muscle.
At this time little research has been performed on human models.
Although the research that has been done shows that myostatin works
basically the same in humans as it does in animals.
Studies indicate myostatin may control muscle fiber type. Research
also shows that altering the bodies metabolism has no effect on
myostatin expression. Studies done on piglets and mice show that
food restriction as well as administration of exogenous growth hormone
did not effect myostatin levels. These studies suggest that myostatin
expression is largely associated with prenatal muscular growth.
High levels of myostatin have been detected in HIV-infected men
in comparison to healthy males. This does not necessarily mean that
myostatin is a factor in muscle wasting. At the present time we
can not be sure of myostatin's role in muscle regulation. Several
authors suggest that myostatin plays a larger role in muscle regeneration
after injury. One study reported that mutations in the human myostatin
gene did not play a role in altering muscle mass in weight trained
subjects.
How does myostatin apply to bodybuilding? This topic has been mentioned
by various authorities in the bodybuilding industry. Mauro Dipasquale
stated in a interview with Testosterone magazine that myostatin
could be the wave of the future. Dan Duchaine and Bill Roberts also
stated that myostatin inhibition could take top level physiques
to an even higher level.
Further research needs to be done with humans before we fully understand
myostatins role in human muscle. Some of the research done on animals
looks very promising, but we are not animals. The biggest problem
facing myostatin research at this time is funding for this type
of research.
Federal funding is unlikely for performance enhancement research.
Scientists believe it is possible that inhibition of myostatin could
possibly help in treating muscle wasting diseases. If this theory
proves reliable it is possible that federal authorities would support
myostatin research for medical purposes.
In conclusion, myostatin presents great possibilities, but at this
time we do not have sufficient evidence to determine myostatin's
role in humans.
References:
1. Canada's Weekly News Review ( 1999 ) [ online
] availabl : http: file://ourpress.com/kfc_superchicken.htm [1999,Sept.28
(volume 1, issue 20 )
2. Falcon , M ( no date ) An overview of possible pathways to increased
muscular size with Dr. Lester Lee . Available : http// www.maxmuscle.com/research/expanding_genes/default.htm
3. Volk , E ( 1999 ) The Myostatin Gene [ online ] Available :
http//www.thinkmuscle.com/exclusive/volk/myostatin.htm [ 1999 ,
December 13 ( Volume 2 , Number 20)
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