Discovery could put exercise gurus out of business
WASHINGTON (AP) - It’s a couch potato’s dream: Instead of sweating and straining, people someday may simply pop a pill to get in shape, say researchers who have identified how muscle cells get stronger from regular exercise.
Researchers at Duke University and the University of Texas Southwestern Medical Center have found the chemical pathway that muscle cells use to build up their strength and endurance.
With that basic knowledge, it may now be possible to develop a pill that pumps up muscle cells without all that exercise, said Dr. R. Sanders Williams, dean of the Duke University of School of Medicine.
But the main target of the research is to help people with heart disease or other conditions that keep them from doing enough exercise to remain healthy, Williams said. “This could lead to drugs that will let people get the health benefits of regular exercise, even if they cannot exercise.”
That could improve the health of patients with heart or lung disease, or could lower the risk of Type II diabetes, for instance.
In the study, Williams and his colleagues created a group of mice with genes that over-expressed a signaling protein called calmodulin-dependent protein kinase, or CaMK. When this signaling protein is activated, it and another protein, calcineurin, trigger the physical changes that muscle cells undergo after intense exercise.
Williams said mice with a high level of CaMK expression developed more mitochondria in muscle cells and saw an increase of a type of cell called the “slow twitch” muscle. Those muscle cells power sustained activity, such as required by marathon runners.
The researchers found that mice with high levels of CaMK developed the same healthy muscle cells as mice that did exercise.
“The effect increases more of the slow twitch muscles, but it also increases the number of mitochondia in the fast twitch muscle cells,” he said. “That is very similar to what happens in very intense training.”
Mitochondria are structures inside a cell that provide energy by metabolizing oxygen and nutrition. Cells with many mitochondria can produce more work over a longer time. Physical training increases the number of mitochondria in muscle cells.