Posted on: Thursday, April 11, 2002

Researchers giving exercise pill good workout in lab mice

Advertiser News Services

WASHINGTON — 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 discovered a protein that directs many of the changes that muscle cells undergo in response to exertion.

Researchers genetically engineered mice to produce extra protein, and at a cellular level the genetically altered animals enjoyed some of the effects of exercise, according to research appearing tomorrow in the journal Science.

The experiments have been carried out in mice only. The researchers said the finding offers clues about why muscle exercise carries broad health benefits, and represents an important first step toward drugs that might help people who can't exercise.

"This discovery could lead to the synthesis of new drugs that will allow individuals to acquire the health benefits of regular exercise, even if they cannot exercise," said R. Sanders Williams, dean of the Duke University School of Medicine. "It has the potential to improve the lives of patients with heart failure, pulmonary disease, renal failure, diabetes and other chronic diseases."

In the government-sponsored study, mice didn't necessarily gain muscle or lose weight. They did develop more mitochondria in their muscle cells. Mitochondria are structures inside cells that transform oxygen and other molecules into energy. People who exercise regularly have more mitochondria in their muscle cells than sedentary people, researchers said.

That's important because muscle cell activity plays a key role in regulating metabolism, and policing levels of fat and sugar in the blood, the researchers said.