RESUMEN
In order to elucidate effects of the exercise intensity on purine catabolism, we performed exhausitve exercise (Exh-ex), 80% VO<SUB>2</SUB>max exercise (80%-ex) and 70% VO<SUB>2</SUB>max exercise (70%-ex) test by a bicycle ergometer, and estimated the purine catabolism by the changes in blood ammonia, plasma oxypurines and urinary oxypurines in five healthy male subjects who were given allopurinol. The results were summarized as follows;<BR>1) Plasma oxypurines concentrations (POP) increased gradually after exercise with each intensity. The order of their maximal levels and of cumulative areas under the curves of POP were exh-ex>80%-ex>70%-ex>control, respectively, and that of urinary excretions of oxypurines was exh-ex>80%-ex>70%-ex≥control.<BR>2) Blood ammonia concentrations (BNH<SUB>3</SUB>) increased sharply after exercise with each intensity. The order of their maximal levels was 80%-ex = exh-ex>70%-ex>control, and that of cumulative areas under the curves of BNH<SUB>3</SUB> was 80%-ex>exh-ex>70%-ex>control.<BR>3) Blood lactate concentrations (BLA) increased sharply after exercise with each intensity. The order of their maximal levels and of cumulative areas under the curves of BLA were exh-ex =80%-ex>70%-ex>control, respectively.<BR>These results suggest that the purine catabolism leading to uric acid production is activated by the physical exercise in the order of increasing intensities. The discrepancy between the increase in ammonia and those in oxypurines suggests that the increased purine catabolic pathway was mediated not only by AMP deamination but also by other factors.