By IANS,
Washington : Two drugs that mimic many of the effects of exercise also increase cellular ability to burn fat, being the first compounds that enhance endurance, according to a study.
Both drugs can be given orally and work by genetically reprogramming muscle fibres to use energy better repeatedly without fatigue.
In lab experiments, mice taking the drugs ran faster and longer than normal mice on treadmill tests. Animals that were given AICAR, one of the two drugs, ran 44 percent longer than untreated animals. The second compound, GW1516, had a more dramatic impact on endurance, but only when combined with exercise.
Ronald M. Evans, Howard Hughes Medical Institute investigator who led the study, said drugs that mimic exercise could offer potent protection against obesity and related metabolic disorders.
They could also help counter the effects of devastating wasting diseases like muscular dystrophy. Evans and his colleagues, who are at the Salk Institute for Biological Studies, published their findings on Thursday.
Concerned about the potential for abuse of the two performance-enhancing drugs, Evans has also developed a test to detect the substances in the blood and urine of athletes who may be looking for ways to gain an edge on the competition.
In 2004, Evans and his colleagues genetically engineered mice that had altered muscle composition and enough physical endurance to run twice as far as normal mice.
These “marathon mice” had an innate resistance to weight gain, even when fed a high-fat diet. “We made these mice and they had low blood sugar, they resisted weight gain, they had low fats in their blood. They were much healthier animals,” Evans said.
“And when we put them on a treadmill, the engineered mice ran twice as far than normal mice – they transformed into remarkable runners.”
Evans, HHMI and the World Anti-Doping Agency are now working to certify the detection system and make it available in time to retroactively test athletes who compete in the 2008 Olympics.
These findings have been published online in Cell.