Posted on 08/18/2002 4:44:56 PM PDT by vannrox
Reprinted from ScienceDaily Magazine ...
Source: University Of Texas Southwestern Medical Center At Dallas
Date Posted: Thursday, August 15, 2002
Web Address: http://www.sciencedaily.com/releases/2002/08/020815072837.htm
Researchers from UT Southwestern Medical Center at Dallas and Harvard Medical School reported in a study in today's issue of Nature that when the protein PGC-1Q is genetically introduced in mice, easily fatigued type II muscle fibers are transformed into fatigue-resistant, mitochondria-rich, or energy-producing, type I muscle fibers that mimic highly exercised muscles.
"When you exercise, your muscles change fiber type specificity, switching from type II fibers to type I fibers," said Dr. Rhonda Bassel-Duby, associate professor of internal medicine at UT Southwestern and a co-author of the study. "When we expressed this protein in the mouse model, we found that the muscle switched from a type II muscle to a type I muscle. It visibly looked like a type I muscle. The presence of this protein alone switched the muscle type."
The protein PGC-1Q, identified by a Harvard Medical School researcher, activates energy production and oxidative metabolism. PGC-1Q is the second protein identified this year that's involved in muscle fiber-type switching. In an April study, reported in Science, UT Southwestern scientists reported that a protein called calcium/calmodulin-dependent protein kinase (CaMK) transformed type II muscle fibers into type I muscle fibers.
"The significance of this finding is that a nuclear cofactor alone was found to be sufficient to drive easily fatigued muscles into fatigue-resistant muscles," said Dr. Hai Wu, second author of the study and a postdoctoral researcher in molecular biology at UT Southwestern.
UT Southwestern researchers performed fatigue resistance measurements in the mice by stimulating the muscles and evaluating the response. The muscles were subjected to continuous electrical stimulation, which mimics muscle contraction during exercise.
"After evaluating the measurements we found that the muscles looked like and functioned as a type I muscle," Bassel-Duby said.
UT Southwestern scientists also performed the muscle-fiber type analysis for today's study and are continuing their own research into the signal transduction pathways that are involved in muscle fiber-type switching.
"The long-term goal of this research is to provide insight and treatment therapy to patients who have muscle fatigue, or are confined to bed rest, to enable them to have stronger, exercised muscles," Bassel-Duby said.
Other UT Southwestern researchers involved in the Nature study were Dr. Eric Olson, chairman of molecular biology, and Dr. Eiji Isotani, a former visiting assistant professor in physiology.
The study was funded by grants from the National Institutes of Health.
Copyright © 1995-2002 ScienceDaily Magazine | Email: editor@sciencedaily.com
Anyone willing to front me the twenty bucks so I get a free second month is in for a ten dollar reward.
I thank you and my blown-out rotator cuff thanks you.
yep. i've got two bad 'uns. the thanks i get for 10 months of hard work at the gym and absolutely NO weight loss (also $450 poorer)
I went along just fine with an occassional cortisone shot until I quit the work outs,
real problems started when I 'grew up' stuck with a job requiring a desk-top and leaned on the damn thing [shoulder].
Doing crunches didn't help the back over the long run either....
Just about the time you feel real good about the work outs:
Back off, do [much] lighter weights and more reps...keep the tone, don't abuse the joints, and you'll stay happier longer.
And, screw the tennie-shoe advertisements, don't run on concrete any more than you have to.
Double WOW! I can't wait till they incorporate this Protein into the fabric of a Speedo!!!
steroids ON STEROIDS
This is a big advancement for those who want to look and perform like emaciated marathoners.
-Scott in KC
It's the left rotator cuff for me - every time.
I refuse to listen to my body, I blow it out, lose interest in lifting, and I have to start from scratch 6 months later as a scrawny little dude. I never learn.
Anabolic steroids cause exercised muscles to "grow" not type switch
A type switch is not growth nor is it tone, it's just that - a type switch. This sort of therapy, if it ever makes it to humans, will only be of benefit to those trying to recover from severe atrophy of the muscles assicated with lots of "bed time". It will allow them to be in a therapy session longer and while shortening the total time spent in therapy (ie. knock off a month or week, from what it was before)
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