THE EFFECT OF HIGH-INTENSITY TRAINING ON PURINE METABOLISM IN MAN

The effect of intermittent high-intensity training on the activity of enzymes involved in purine metabolism and on the concentration of plas ma purines following acute shortterm intense exercise was investigated . Eleven subjects performed sprint training three times per week for 6 weeks. Muscle biopsies for determination of enzyme activities were ob tained prior to and 24 h after the training period. After training, th e activity of adenosine 5'-phosphate (AMP) deaminase was lower (P < 0. 001) whereas the activities of hypoxanthine phosphoribosyl transferase (HPRT) and phosphofructokinase were significantly higher compared wit h pre-training levels. The higher activity of HPRT with training sugge sts an improved potential for rephosphorylation of intracellular hypox anthine to inosine monophosphate (IMP) in the trained muscle. Before a nd after the training period the subjects performed four independent 2 -min tests at intensities from a mean of 106 to 135% of VO2max. Venous blood was drawn prior to and after each test. The accumulation of pla sma hypoxanthine following the four tests was lower following training compared with prior to training (P < 0.05). The accumulation of uric acid was significantly lower (46% of pre-training value) after the tes t performed at 135% of VO2max (P < 0.05). Based on the observed altera tions in muscle enzyme activities and plasma purine accumulation, it i s suggested that high intensity intermittent training leads to a lower release of purines from muscle to plasma following intense exercise a nd, thus, a reduced loss of muscle nucleotides.