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Improvement of muscular oxidative capacity by training is associated with slight acidosis and ATP depletion in exercising muscles
Author(s) -
Ravalec Xavier,
Le Tallec Nathalie,
Carré François,
de Certaines Jacques D.,
Le Rumeur Elisabeth
Publication year - 1996
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/(sici)1097-4598(199603)19:3<355::aid-mus12>3.0.co;2-r
Subject(s) - phosphocreatine , creatine kinase , creatine , oxidative phosphorylation , medicine , skeletal muscle , acidosis , endocrinology , adenosine triphosphate , citrate synthase , creatine monohydrate , chemistry , muscle contraction , metabolic acidosis , biochemistry , energy metabolism , enzyme , pathology , alternative medicine , placebo
Metabolic and mechanical properties of female rat skeletal muscles, submitted to endurance training on a treadmill, were studied by a 60‐min in vivo multistep fatigue test. 31 P‐NMR was used to follow energy metabolism and pH. Mechanical performance was greatly improved in trained muscles. The oxidative capacity of the skeletal muscles was evaluated from the relationship between ADP calculated from the creatine kinase equilibrium and work and from the measure of the rate of phosphocreatine (PCr) resynthesis following exercise. In trained muscles, ADP production was lower per unit of mechanical performance, showing an improvement of oxidative metabolism. However, the PCr resynthesis rate was not modified. Slight acidosis and ATP depletion were observed from the beginning of the fatigue test. These modifications suggest changes of the creatine kinase equilibrium favoring mitochondrial ATP production. Our results indicate that muscle status improvement could be accompanied by ATP depletion and minimal acidosis during contraction; this would be of particular importance for objective evaluation of muscle regeneration processes and of gene therapy in muscle diseases. © 1996 John Wiley & Sons, Inc.