According to the researchers, their finding will offer important insights into the machinery that powers muscle development and the physiological changes produced by exercise. The finding also suggests a route to designing drugs that enhance muscle development and mimic all the benefits of exercise. The researchers said such drugs could aid patients whose debilitating diseases prevent them from exercising. The researchers recognize that such drugs already being tested by pharmaceutical companies could be abused as a way to enhance athletic performance.
Led by Howard Hughes Medical Institute investigator Ronald M. Evans at The Salk Institute, the researchers published their findings online August 24, 2004, in the journal Public Library of Science Biology. Other co-authors are from Seoul National University in Korea.
In their studies, the researchers were exploring the effects of altering the gene for a protein called PPAR-delta -- a master regulator of numerous genes -- to enhance that protein's activity. According to Evans, they had not expected the profound and far-reaching physiological effects of this single genetic alteration.
"In previous work, we had shown that in various tissues, particularly adipose tissues, activating PPAR-delta increased fat burning and, as a result, decreased fat-tissue mass," said Evans. "Going into this experiment, the possibility of an effect on muscle fibers was not on our radar screen."
However, when the researchers produced mice with enhanced PPAR-delta activity, they saw a major transformation in skeletal muscle fibers. The mic
Contact: Jennifer Michalowski
Howard Hughes Medical Institute