EFFECTS OF EXERCISE TRAINING ON PLASMA TOTAL HOMOCYSTEINE AND GLUTATHIONE LEVELS: THE HERITAGE FAMILY STUDY

41 Homocysteine and glutathione are sulfur-containing aminoacids that could play a role in the oxidant/antioxidant balance during exercise. We investigated the influence of a 20-wk endurance exercise training program performed at the Quebec Clinical Center on plasma total homocysteine (tHcy) and glutathione (tGluta) levels in 140 subjects (74F, 66M, aged 17 - 62 yrs) from 28 families (51 parents, 89 children) participating in the HERITAGE Family Study. Aminothiols were measured by HPLC and other biochemical variables by routine techniques. At baseline, tHcy levels were positively correlated with age (p=0.01), serum creatinine and uric acid (p<0.001), albumin (p<0.05), WHR and fat free mass (p=0.01). Females had lower levels of tHcy than males (7.5 vs 8.8 μmol/L, p<0.001), whereas tGluta was not significantly different between genders (4.3 vs 4.7 μmol/L). Parents had higher tHcy and lower tGluta levels than their children (8.7 vs 7.8 μmol/L and 4.1 vs 4.7 μmol/L, respectively; p<0.05). Subjects responded to exercise training with a significant 5.5% mean increase in tHcy (p=0.0003) and 7.6% in tGluta levels (p<0.05). These changes were accompanied by increases in serum uric acid level (p=0.005), in VO2max and fat free mass(p<0.0001) and a decrease in serum albumin (p=0.005). However, the relationship between changes in tHcy or tGluta levels and changes in these variables was not statistically significant. Apart from the increase in VO2max which was larger in females than in males (p=0.02), there were no gender or generation differences in the response of the measured variables to exercise. We conclude that exercise induces increases in plasma tHcy and tGluta levels which may be, at least in part, a consequence of oxidant/antioxidant changes occurring during endurance training.