Alterations in purine metabolism in middle-aged elite, amateur, and recreational runners across a 1-year training cycle

Abstract

Changes in purine derivatives may be considered as signs of training-induced metabolic adaptations. The purpose of this study was to assess the effect of a 1-year training cycle on the response of hypoxanthine (Hx) concentration and Hx-guanine phosphoribosyltransferase (HGPRT) activity. Three groups of middle-aged male runners were examined: 11 elite master runners (EL; 46.0 ± 3.8 years), 9 amateur runners (AM; 45.1 ± 4.7 years), and 10 recreational runners (RE; 45.9 ± 6.1 years). Plasma Hx concentration and erythrocyte HGPRT activity were measured in three characteristic training phases of the annual cycle. Significant differences in post-exercise Hx concentration and resting HGPRT activity were demonstrated between the EL, AM, and RE groups across consecutive training phases. The EL group showed lowest Hx concentration and highest HGPRT activity compared to the AM and RE groups. Analogous differences were observed between the AM and RE groups during specific preparation. For the EL group, the changes were observed across all examinations and the lowest Hx concentration and highest HGPRT activity were found in the competition phase. Significant change was also revealed in the AM group between the general and specific preparation, but not in the competition phase. No significant changes were found in the RE runners who did not use anaerobic exercise in their training. In conclusion, a long-lasting endurance training, incorporating high-intensity exercise, results in significant changes in purine metabolism, whereas training characterized by constant low-intensity exercise does not. Plasma Hx concentration and erythrocyte HGPRT activity may be sensitive indicators of training adaptation and training status in middle-aged athletes.

The Effect of Training on Erythrocyte Energy Status and Plasma Purine Metabolites in Athletes

“…Admittedly, the concentration of guanine nucleotides did not change throughout the annual training cycle in any studied group, but it was consistently higher in athletes comparing to the recreationally-trained runners. Similarly to previous studies [13][14][15], we showed that erythrocyte HGPRT activity peaked in the competition phase. Moreover, a gradual reduction in plasma Ino and Hx concentrations and increased plasma Ado concentration were visible in competitive athletes from the transition to the competition training phase.…”

“…In disciplines based on running, sprint and endurance training regimes have usually equal time frames but very different characteristics of training loads resulting from distinct training goals.Thus far, changes in erythrocyte energy status and purine nucleotide catabolites concentration were not yet explored also during a longer period or under prolonged training regime. Reports based on one-year training cycles only focused on changes in plasma hypoxanthine (Hx) concentration and erythrocyte hypoxanthine-guanine phosphoribosyltransferase (HGPRT) activity [13][14][15]. It was demonstrated that sprint training, predominated by high-intensity exercise, but also endurance training supplemented by high-intensity loads, led to a decrease in plasma Hx and an increase in erythrocyte HGPRT activity.…”

The Effects of a Short-Term High-Intensity Interval Training (HIIT) on the Levels of Serum Hypoxanthine-Guanine Phosphoribosyltransferase (HGPRT) Enzyme and Some Variables of Purine Nucleotide Cycle

“…Therefore, in this study that reported high levels of hypoxanthine, it can be concluded that ATP levels have not been renovated yet. Zielinski (2013), comparing groups of elite athletes and recreational amateurs, showed that elite athletes had a lower increase at hypoxanthine and xanthine rates and amateur and recreational athletes had more purine nucleotides excretion (9). Thus, in the case of the present study in which the participants had not been trained, it is likely that they were not able to recover appropriately during demolition and reconstruction of ATP in the training and recycling period (9).…”

“…In fact, it can be noted that higher HGPRT activity after high intensity training in which the dominant energy is anaerobic is an indicator of a better salvage pathway for reconstruction of adenine purine nucleotides (6). An increase in HGPRT after training has also been previously reported (9,15,25). It has also been indicated that in 4 seasons of the annual training cycle (adopted from Bompa, 1999), the match season in which the training moved towards anaerobic, the relaxing activity of this enzyme was high, and this is consistent with the findings of the present study because HIIT activities in which the major energy system is anaerobic can increase this enzyme and as a result, improve the salvage pathway purine nucleotides (26).…”

“…Uric acid is the final product of purine in human, known as an endogenous scavenger, which is responsible for much of the body antioxidant capacity against free radicals and radical damages (7). Several factors such as exercise and physical activity affect the levels of uric acid and other variables of purine nucleotides so that, through compatibility with exercise, the HGPRT enzyme activity increases, and ultimately lower levels of uric acid, plasma xanthine, and hypoxanthine plasma are seen in individuals, particularly among trained individuals who are most compatible with exercise compared to less trained individuals (9).…”