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Muscle performance and fitness are partly determined by how wellyour muscle cells use sugar as a fuel source. In turn, exercisingimproves the muscle's ability to take up sugars from thebloodstream and burn them for energy. On the flip side, conditionsthat reduce physical activity -- such as obesity or chronic disease -- reduce the muscle's capacity to burn sugar.A new study by researchers at Sanford-Burnham Medical ResearchInstitute (Sanford-Burnham) unravels a mechanism that re-programsmetabolic genes in muscles in a way that increases their capacityto use sugar. When activated in mice, this metabolic re-programmingdramatically improves exercise performance. These findings,published Dec. 1 in Genes & Development, reveal new targets that could be explored to increase the abilityof muscles to burn sugars -- an avenue that could ultimately leadto new prevention or treatment methods for obesity, metabolicsyndrome, and diabetes . "Essentially, these transgenic mice are capable of storing andburning sugars at rates usually only seen in the trained athlete.This allows for supranormal athletic performance," said Daniel P.Kelly, M.D., scientific director at Sanford-Burnham's Lake Nonacampus in Orlando, Fla. and senior author of the study. Dr. Kelly's mice are special because they're engineered to producethe protein PPAR / in their muscle tissue. PPAR / is anuclear receptor, a type of protein that binds DNA to turn genes onor off in response to outside signals -- in this case, genesspecific to muscle metabolism. Previous studies have shown thatmice with high PPAR / levels in their muscles have increasedexercise capacity. In this study, the researchers discovered whythat is -- the muscles of PPAR / mice are better than normalmice at taking up sugar from the bloodstream, storing it, andburning it for energy. Dr. Kelly and his team also found that PPAR / mice are superfit. Compared to normal mice, they ran longer and faster yetgenerated lower amounts of lactic acid, considered the chiefmediator of exercise-induced muscle pain. How does PPAR / pull it off? It turns out that exercisestimulates cells to assemble a complex of three proteins: 1)PPAR / ; 2) a protein that maintains cellular energy balance(adenosine monophosphate-activated protein kinase or AMPK); and 3)a protein that helps activate muscle-specific genes (MEF2A).Together, these proteins switch on the gene that produces lactatedehydrogenase, an enzyme that directs sugar-derived metabolitesinto mitochondria, where complete burning of the fuel is possible-- effectively converting sugar to energy. It's likely that thisnovel mechanism helps activate other genes involved in musclefitness as well. "Given the association of obesity and insulin resistance with dietsenriched in simple sugars, we find these results promising as astep towards new therapeutics," Dr. Kelly said. "Previously,members of the PPAR protein family have proven to be difficult drugtargets due to the wide variety of effects they have in a cell.However, the findings in this study suggest that strategies foractivating only a subset of events downstream of PPAR / arepossible. This could lead to favorable metabolic effects on muscleand other tissues." Additional References Citations. I am an expert from wwsgift.com, while we provides the quality product, such as Cool Bike Bell , PVC Keychain, Universal Travel Adaptor,and more.
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