Correlation

loading plot (1st and 2nd PLS component) of PLS2 using NMR variables as X and selected proteomic spots as Y. Jack knifing has been applied to EGFR inhibitor eliminate insignificant variables. The inner and outer ellipses refer to 50 percent and 100 percent explained variance in X and Y, respectively. The validated explained variances are 100%/0% for X and 51%/18% for Y, the 1st and the 2nd component, respectively. The results from the proteomic data indicate an antioxidative effect of CMH on the cells as two thioredoxin reductases (peroxiredoxin-4 and thioredoxin dependent peroxide reductase) BMS202 were up-regulated. On the basis of this, the overall intracellular antioxidative capacity was analyzed in myotubes after pre-incubation with CMH for 24 h. The protective effect of CMH pre-incubation was supported by a reduced intracellular DCFH2 oxidation with increasing concentrations of CMH (Figure 4). Figure 4 Intracellular oxidation of 2,7-dichloroflourescein. Oxidation of intracellular 2,7-dichloroflourescein this website in myotube cultures exposed to 100 μM H2O2 after pre-incubation with increasing

amounts of creatine monohydrate (CMH) for 24 h. Discussion The identified differentially regulated proteins (Table 2) are related to different cellular functions. Malate dehydrogenase is central in the energy metabolism, GRP75 and GRP78 are glucose regulated stress proteins, the filament protein vimentin is involved in maintaining cell integrity, and perturbation of the antioxidant defence system is indicated by peroxiredoxin-4 and thioredoxin dependent peroxide reductase. The reason why malate dehydrogenase is elevated in creatine treated cultures Lck is not known. However, we speculate that increased re-synthesis of glycogen is involved following treatment with CMH. This is based on the following considerations. In muscle creatine phosphate is an available energy source for muscle contraction during anaerobic conditions: This reaction is under the control of creatine phosphokinase. Addition of CMH increases intra cellular concentrations of creatine (Figure 1) and this in turn will force the

equilibrium to the right resulting in a higher level of creatine phosphate and ADP. Reduced ATP and increased ADP will increase the ratio of ADP:ATP which increases the rate of glycogenolysis. Thus, to restore ATP glycogen is degraded causing an elevated intracellular glucose level, which in the present study was indicated by down regulation of the glucose regulated protein precursors GRP75 and GRP78, both of which has been shown to increase with glucose starvation in the cell [33]. Following ATP restoration, glyconeogenesis is stimulated (by ATP). The substrate for the re-synthesis of glycogen is oxaloacetate and in the mitochondria oxaloacetate is converted to malate in order to enable the transport to the cytoplasm.