Recovery of free ADP, Pi, and free energy of ATP hydrolysis in human skeletal muscle.
We measured significant undershoots of the concentrations of free ADP ([ADP]) and Pi ([Pi]) and the free energy of ATP hydrolysis (DeltaGATP) below initial resting levels during recovery from severe ischemic exercise with 31P-nuclear magnetic resonance spectroscopy in 11 healthy sports students. Undershoots of the rate of oxidative phosphorylation would be predicted if the rate of oxidative phosphorylation would depend solely on free [ADP], [Pi], or DeltaGATP. However, undershoots of the rate of oxidative phosphorylation have not been reported in the literature. Furthermore, undershoots of the rate of oxidative phosphorylation are unlikely because there is evidence that a balance between ATP production and consumption cannot be achieved if an undershoot of the rate of oxidative phosphorylation actually occurs. Therefore, oxidative phosphorylation seems to depend not only on free [ADP], [Pi], or DeltaGATP. An explanation is that acidosis-related or other factors control oxidative phosphorylation additionally, at least under some conditions.
Wackerhage
H
H
Department of Physiology, German Sports University, D-50933 Cologne, Germany. h.wackerhage@uclan.ac.uk
Hoffmann
U
U
Essfeld
D
D
Leyk
D
D
Mueller
K
K
Zange
J
J
D000244:Adenosine Diphosphate / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000328:Adult; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007511:Ischemia / Q000503:physiopathology; D007537:Isometric Contraction / Q000502:physiology; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010085:Oxidative Phosphorylation; D010710:Phosphates / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism; D013816:Thermodynamics
D010710:Phosphates; D010725:Phosphocreatine; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate