Maximal physical exertion is accompanied by increased degradation of purine nucleotides in muscles with the products of purine catabolism accumulating in the plasma. intensity and at the 30th min of rest. We also examined the effect of muscular exercise on adenylate (guanylate) energy charge-AEC (GEC) and on the concentration of nucleosides (guanosine inosine adenosine) and hypoxanthine. We have shown Malol in this study that a standardized physical exercise with increasing intensity leads to an increase in IMP concentration in red blood cells immediately after the exercise which with a significant increase in Hyp concentration in the blood suggests that Hyp was included in the IMP pool. Restitution is accompanied by an increase in the ATP/ADP and ADP/AMP ratios which indicates an increase Malol in the phosphorylation of AMP and ADP to ATP. Physical effort applied in this study did not lead to changes in the concentrations of guanine and pyridine nucleotides in red blood cells. adenosine deaminase (EC 18.104.22.168) adenosine kinase (EC 22.214.171.124) AMP deaminase … Physical exercise causes an oxygen deficit in the working muscles. The evolving hypoxia impairs oxidative ATP resynthesis which increases ATP degradation accompanied by the accumulation of IMP (Stathis et al. 1994; Hellsten et al. 1999). Most of the IMP is very quickly resynthesized to ATP during restitution but part of the IMP is dephosphorylated which results in the production of Ino and Hyp (Stathis et al. 1994). The products of purine catabolism not recovered intramuscularly via purine salvage efflux the muscle and are collected in the plasma (Bangsbo et al. 1992; Hellsten-Westing et al. 1994; Zhao et al. 2000). Thanks to membrane transporters nucleosides and purine bases (mainly hypoxanthine) are in equilibrium between plasma and red blood cells where they constitute the substrate in the salvage reactions. These processes involve PRPP adenine phosphoribosyltransferase (APRT) hypoxanthine-guanine phosphoribosyltransferase (HGPRT) and nucleoside kinases (Dudzinska et al. 2006). Many in vitro studies have shown that nucleosides and purine bases may participate in the resynthesis of adenine nucleotides in red blood cells (Bontemps et al. 1986; Berman et al. 1988; Van der Berghe and Bontemps 1990; Kim 1990; Komarova et al. 1999). Kim (1990) and Komarova et al. (1999) demonstrated the participation of adenosine in the resynthesis of the adenine nucleotide pool especially under conditions of high Pi concentrations. The results of those experiments suggest the participation of Pi in the stimulation of adenosine kinase. In contrast Van der Berghe and Bontemps (1990) and Bontemps et al. (1986) reported an Pi-induced inhibition of the activity of 5′-nucleotidase and AMP deaminase. Thus the increase in erythrocyte and plasma Pi accompanying physical effort (Yamamoto et al. 1994) may lead to changes in the activities of enzymes involved in purine metabolism. In addition one of the phenomena regularly associated with intense physical effort is metabolic acidosis. The increase in the concentration of hydrogen ions in body fluids is greater the greater the intensity of effort. A fall in pH in red blood cells Malol results in a decrease in ADP and 2.3 DPG (allosteric inhibitors of PRPP synthetase EC 126.96.36.199) with a concomitant increase in intracellular Pi (activator of PRPP synthetase) and ATP (Berman et al. 1988). Thus intense physical activity Rabbit Polyclonal to OR5K1. is likely to encourage increased synthesis of PRPP-a co-substrate in reactions catalyzed by APRT and HGPRT. Berman et al. (1988) reported that the Malol uptake of Hyp and accumulation of IMP in red blood cells are significantly increased at an acid pH high external phosphate concentrations and low . In addition they suggested that erythrocytes could play a role in the removal of Hyp from anoxic tissue. So far there has been few reports of post-exercise changes in the erythrocyte concentration of adenine guanine and pyridine nucleotides. Moreover existing literature is very inconsistent in this respect (Makarewicz et al. 1980; Harkness et al. 1983; Yamamoto et al. 1994). Therefore we decided to measure the concentrations of adenine (ATP ADP AMP) inosine (IMP) guanine (GTP GDP GMP) as well as pyridine (NAD NADP) nucleotides in red blood cells immediately after standardized physical effort with increasing intensity and at the 30th min of.