Control of phosphocreatine resynthesis during recovery from exercise in human skeletal muscle

✍ Scribed by G. J. Kemp; D. J. Taylor; G. K. Radda

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 671 KB
• Volume: 6
• Category: Article
• ISSN: 0952-3480
• DOI: 10.1002/nbm.1940060111

✦ Synopsis

Information about the control of mitochondrial function in skeletal muscle in uivo can be obtained from the relationship between the rate of mitochondrial oxidation and the intracellular concentrations of phosphorus metabolites, although the analysis is complicated by the constraints imposed by the creatine kinase equilibrium. The rate of phosphocreatine (PCr) recovery after exercise measured by "P MRS is an estimate of net oxidative ATP synthesis. Analysing such data from normal and abnormal human muscle, we show that the approximately exponential recovery kinetics of ADP and PCr imply that the rate of PCr resynthesis has a hyperbolic dependence on [ADP] but remains approximately linear with respect to the concentration of orthophosphate (Pi) and therefore also [PCr] and [creatine]. Both kinds of relationship are consistent with experimental data from exercising animal muscle and also with data from isolated mitochondria which suggest kinetic control of mitochondrial ATP synthesis of [ADPI. These relationships are altered in proven mitochondrial disease. This analysis offers a way to quantify mitochondrial function and its abnormalities in viuo.