I need to get my hands on this.
Experiment with mice sheds light on man’s muscle
Karl B. Hille, The Examiner2007-08-29 07:00:00.0Current rank: # 317 of 5,541 BALTIMORE -
Mighty Mouse now has good company.
The Johns Hopkins scientist who first showed how the absence of the protein myostatin leads to oversized muscles in mice and men has found a second protein, follistatin, which amplifies the first effect.
The results are some pretty muscular mice, said Dr. Se-Jin Lee, whose work appears today in Public Library of Science One. Mice missing the gene that makes myostatin have about twice the body muscle as normal. However, those which also overproduce follistatin double their muscle mass again.
“Right now there’s a lot of focus in pharmaceutical companies trying to block myostatin in order to promote muscle growth,” Lee said. “In order to maximize the effect you need to add the other protein.”
This added muscle booster could help “beef up” livestock or promote muscle growth in patients with muscular dystrophy and other wasting diseases, he said. However, “the potential for misuse is huge. Already there’s been a lot of buzzing in the professional bodybuilding community about how to exploit that pathway for muscle gain,” Lee said.
Muscular dystrophy is classified as a rare disease by the National Institutes of Health, meaning that the main form, Duchenne Muscular Dystrophy, affects fewer than 200,000 Americans. Symptoms include muscle wasting, poor balance and in severe cases weakening of the heart.
However, outside of one case of a German man with a genetic mutation, no one has studied the potential effects on people, Lee said.
Lee first discovered follistatin could block myostatin’s effectiveness in muscle cells grown in a dish. Normal mice bulked up when given the protein, just like mice with their myostatin gene blocked. He then genetically engineered a mouse that both lacked myostatin and made extra follistatin.
If follistatin was increasing muscle growth solely by blocking myostatin, then Lee surmised that follistatin would have no added effect in the absence of myostatin.
“To my surprise and delight, there was an additive effect,” he said. These muscular mice averaged a 117 percent increase in muscle fiber size and a 73 percent increase in total muscle fibers compared with normal mice.