Skeletal muscle phosphocreatine
recovery in exercise-trained humans is dependent on O2 availability.
Inhibition of muscle phosphocreatine
resynthesis by caffeine after creatine loading.
Although a detailed examination of the muscular system of the mutant mice revealed the inability to perform the burst activity; phosphocreatine
and ATP concentrations appeared normal in CK-M-deficient skeletal muscles.
These spectra showed the relative amounts of inorganic phosphorus and the metabolites phosphocreatine
and adenosine triphosphate -- normally present in minute quantities and very difficult to detect.
Increased oxygen availability improves intermittent sprint performance by increasing aerobic contribution for the re-synthesis of adenosine triphosphate during sprint and accelerating the re-synthesis of phosphocreatine
after sprint (Glaister, 2005).
A deep fall in contractile function allows them to conserve limited stores of ATP and phosphocreatine
. This is realized by means of limiting [Ca.sup.2+] entry into cells  due to the shortening of action potential and early release of [K.sup.+], which gradually reduces excitability of cardiomyocytes.
The different work-to-rest ratio in the two exercises influenced the metabolism, because it has been shown that a shorter rest time between repeated sprints might result in smaller restoration of phosphocreatine
Creatine kinase catalyzes the conversion of creatine and consumes adenosine triphosphate (ATP) to create phosphocreatine
and adenosine diphosphate, therefore ATP can be generated from phosphocreatine
The extent to which an individual can maintain their sprint performance is known as "repeated sprint ability" (RSA)  which is largely dependent on the extent of Phosphocreatine
(PCr) resynthesis  and the removal of hydrogen ions ([H.sup.+]) from the muscle during recovery between bouts.
"Pyruvate Utilization, Phosphocholine and Adenosine Triphosphate (ATP) Are Markers of Human Breast Tumor Progression." (3) This study compared breast cancer cells with normal breast cells and found a 30% decrease in ATP levels and an 83% decrease in phosphocreatine
levels "suggests impaired mitochondria' metabolism in the breast carcinoma cell lines." "These results demonstrate that diminished mitochondrial energy generation may be quantitatively related to the progression state of human breast cancer cells." That is, malignancy potentially correlates with mitochondrial dysfunction.
rosea did not improve blood oxygenation after induced hypoxia and skeletal muscle phosphocreatine
(PCr) recovery after exhaustive exercise respectively.
For assessment of AC activity, aliquots of the same membrane preparation were incubated for 30 min at 30[degrees]C with final concentrations of 100 mM Tris-HCl (pH 7.4), 10 mM theophylline, 1 mM ATP, 2 mM Mg[Cl.sub.2], 1 mg/mL bovine serum albumin, and a creatine phosphokinase-ATP-regenerating system consisting of 10 mM sodium phosphocreatine
and 8 IU/mL phosphocreatine
kinase, with 10 [micro]M GTP in a total volume of 250 [micro]L.