Take two and run farther in the morning: drugs improve muscular endurance in lab mice.
Different mice given a second drug did even better, besting the running time and distance of their drug-free, exercising peers by up to 75 percent, researchers reported in the Aug. 8 Cell. But this drug, called GW1516, worked only if the mice regularly exercised while taking it.
All this just in time for the Olympics.
"I wouldn't be surprised if there are some athletes who already have" acquired GW1516, says lead scientist Ronald Evans of the Salk Institute for Biological Studies in La Jolla, Calif. The drug is already made in India "by the bucket load," Evans says, and United Kingdom pharmaceutical company GlaxoSmithKline has tested it in clinical trials as a cholesterol drug.
Evans says he has already provided sensitive tests for both drugs to the World Anti-Doping Agency, the group based in Montreal, Canada, that oversees drug testing for the Olympics.
Illicit use by athletes isn't the only potential use for these muscle endurance--boosting drugs. "Perhaps you can treat people who are disabled or who are unable to exercise," comments Erik Richter, a muscle physiologist at the University of Copenhagen in Denmark. "They would benefit from this type of drug."
Evans made headlines in 2004 after genetically engineering mice with extra copies of the gene PPAR-delta, which helps regulate muscle metabolism. Hopping onto treadmills for the first time, these mice ran about twice as long as normal mice. The second drug, GW1516, works by stimulating this gene in normal mice. AICAR targets the protein AMP kinase.
Both drugs converted some of the mice's muscle cells from the sugar-burning, speedy type to the fat-burning, endurance type. But more research is needed to show whether the drugs induce any of the other benefits of exercise, such as cardiovascular fitness, bone strength and hormonal changes.
Richter says he doubts a single pill will soon replace exercise. "If you think that exercise is good for you," he says, "why not just do it instead of sitting on the couch and popping a bunch of pills?"
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|Title Annotation:||Genes & Cells|
|Date:||Aug 30, 2008|
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