“Background Creatine is a glycine-arginine metabolite synthesized in the liver, pancreas, and kidneys and is naturally stored by skeletal and cardiac muscles as an
energy supplier in the phosphocreatine form . Muscle phosphocreatine plays a key role in anaerobic ATP production in muscles via the highly exergonic reaction catalyzed by creatine kinase. Thus, creatine monohydrate has become an increasingly popular dietary supplement, particularly for improvement of explosive strength performances [2, 3]. Recent findings have also proposed that creatine supplementation could efficiently restrain oxidative processes in vitro[4, 5]. At least two antioxidant mechanisms are currently selleck chemicals llc suggested for creatine: (i) direct scavenging of hydroxyl (HO·) and nitrogen dioxide (NO2 ·) radicals [6–8] by the creatine N-methylguanidino moiety; and (ii) lasting use of anaerobic AR-13324 datasheet energy-supplying pathways
because of accumulated creatine and preserved glycogen in skeletal muscles [9–11]. A plethora of data has revealed that reactive oxygen species (ROS) are overproduced during and after anaerobic/resistance exercise, but from cellular sources other than mitochondria [12, 13]. Induced by an apparent ischemia-reperfusion process during intense contractile selleckchem activity of the resistance exercise, accumulating concentrations of AMP in exhausting muscle fibers activate the capillary enzyme xanthine oxidase – belonging to the purine catabolic pathway – which catalyzes the conversion of hypoxanthine into uric acid with concomitant
overproduction of superoxide radicals (O2 ·-) and hydrogen peroxide (H2O2) . In turn, O2 ·- and H2O2 are closely related to the production of the highly reactive hydroxyl radical (HO·) by iron-catalyzed reactions (Eqs. 1 and 2) that harmfully initiate PIK3C2G oxidizing processes in cells, such as lipoperoxidation . (1) (2) Although some information linking iron metabolism and oxidative stress in exercise/sports is currently available, data reporting changes in iron homeostasis of plasma during/after one single bout of exercise compared to antioxidant responses are still scarce. Sources of iron overload in plasma during/after exercise are also unclear. Noteworthy, many authors have reported evidence of a “sport anemia” syndrome in athletes and experimental animals – especially in females – as a result of chronic iron deficiency imposed by prolonged training periods [16, 17]. Thus, based on iron-redox chemistry, progressive ROS overproduction could be triggered by iron overload in plasma and extracellular fluids during/after anaerobic exercise [18, 19]. Together, these redox changes have been increasingly associated to lower athletic performance, early fatigue, inflammatory processes, and higher risks of post-exercise injuries [20–22].