Effects of exercise and grape juice ingestion in combination on plasma concentrations of purine bases and uridine.

BACKGROUND: Since grape juice contains considerable amounts of fructose, which may increase the plasma concentration of urate, the combination of exercise and grape juice may increase the plasma concentration of urate to a greater degree than grape juice or exercise alone. METHODS: We performed 3 experiments with 6 healthy male Japanese. The first was exercise alone (exercise alone experiment), the second was grape juice ingestion alone (grape juice alone experiment), and the third was a combination of exercise and grape juice ingestion (combination experiment). RESULTS: In the exercise alone experiment, the concentrations of purine bases and uridine in plasma, and lactate in blood, as well as the urinary excretion of oxypurines were increased, whereas the urinary excretion of uric acid and fractional excretion of purine bases were decreased. In the grape juice alone experiment, the concentrations of purine bases and uridine, as well as lactate in blood were increased, whereas the fractional excretion of uric acid was decreased. In the combination experiment, the concentrations of purine bases and uridine in plasma, and lactate in blood, as well as the urinary excretion of oxypurines were increased, whereas the urinary excretion of uric acid and fractional excretion of hypoxanthine, xanthine, and uric acid were decreased. The increase in plasma concentration of urate by the combination of exercise and grape juice was greater than that by each alone, though it was not significantly different from the sum of increases in those 2 experiments. CONCLUSION: Increases in adenine nucleotide degradation and lactic acid production caused by both exercise and grape juice ingestion play an important role in the increase in plasma concentration of urate, while those in combination have an additive effect on that concentration.

Plasma concentrations and urinary excretion of purine bases (uric acid, hypoxanthine, and xanthine) and oxypurinol after rigorous exercise.

To investigate the effects of exercise on the plasma concentrations and urinary excretion of purine bases and oxypurinol, we performed 3 experiments with 6 healthy male subjects. The first was a combination of allopurinol intake (300 mg) and exercise (VO2max, 70%) (combination experiment), the second was exercise alone (exercise-alone experiment), and the third was allopurinol intake alone (allopurinol-alone experiment). In the combination experiment, exercise increased the concentrations of purine bases and noradrenaline in plasma, as well as lactic acid in blood and the urinary excretion of oxypurines, whereas it decreased the urinary excretion of uric acid and oxypurinol as well as the fractional excretion of hypoxanthine, xanthine, uric acid, and oxypurinol. In the exercise-alone experiment, exercise increased the concentrations of purine bases and noradrenaline in plasma, lactic acid in blood, and the urinary excretion of oxypurines, whereas it decreased the urinary excretion of uric acid and fractional excretion of purine bases. In contrast, in the allopurinol-alone experiment, the plasma concentration, urinary excretion, and fractional excretion of purine bases and oxypurinol remained unchanged. These results suggest that increases in adenine nucleotide degradation and lactic acid production, as well as a release of noradrenaline caused by exercise, contribute to increases in plasma concentration and urinary excretion of oxypurines and plasma concentration of urate, as well as decreases in urinary excretion of uric acid and oxypurinol, along with fractional excretion of uric acid, oxypurinol, and xanthine. In addition, they suggest that oxypurinol does not significantly inhibit the exercise-induced increase in plasma concentration of urate.