AICAR, GW1516 Are An Exercise In A Pill
AICAR and GW1516 experiments suggest that these two drugs, also called exercise in a pill, might protect against gaining weight on a high-fat diet, which might make it useful for treating obesity.
Researchers have identified two drugs, AICAR and GW1516, that mimic many of the physiological effects of exercise. The drugs increase the ability of cells to burn fat and are the first compounds that have been shown to enhance exercise endurance.
Both AICAR and GW1516 can be given orally and work by genetically reprogramming muscle fibers so they use energy better and contract repeatedly without fatigue. In laboratory 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, the 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 muscle-wasting diseases like muscular dystrophy. Evans and his colleagues, who are at the Salk Institute for Biological Studies, published their findings on July 31, 2008, in an advance online publication in the journal Cell.
Concerned about the potential for abuse of the two performance-enhancing drugs AICAR and GW1516, Evans has also developed a test to detect the substances in the blood and urine of athletes who may be looking for way 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.”