Myostatin by Strength Coach Jamie Hale
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.
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/
3. Volk , E ( 1999 ) The Myostatin Gene [ online ] Available :
myostatin.htm [ 1999, December 13 ( Volume 2 , Number 20)