Oxidative stress in response to forearm ischemia-reperfusion with and without carnitine administration

We have recently noted a decrease in lipid peroxidation with oral intake of glycine propionyl-L-carnitine (GPLC). However, these findings were observed at rest, and in previously sedentary subjects.

We determined the effect of GPLC on oxidative stress biomarkers at rest and in response to reactive hyperemia in exercise-trained men. Using a double-blind, crossover design, 15 healthy men were assigned to a placebo and GPLC (4.5 g/day) in random order, for four weeks, with a two-week washout between assignments. Blood samples were collected at rest and at 0, 3, and 10 minutes following a protocol of ischemia-reperfusion, and analyzed for lactate, malondialdehyde (MDA), F(2)-isoprostanes (F(2)-iso), hydrogen peroxide (H(2)O(2)), xanthine oxidase activity (XO), hypoxanthine (HYPO), total (TGSH) and oxidized (GSSG) glutathione, and Trolox-equivalent antioxidant capacity (TEAC).

No condition or condition by time interaction effects were noted (p>0.05). Time effects were noted for lactate (p<0.0001), MDA (p=0.02), H(2)O(2) (p=0.0003), XO (p=0.03), HYPO (p<0.0001), TGSH (p=0.02), and GSSG (p<0.0001), with peak values noted at 0 minutes post for lactate, MDA, TGSH, and GSSG, at 3 minutes post for H(2)O(2) and XO, and at 10 minutes post for HYPO. F(2)-iso and TEAC were unaffected by treatment or protocol (p>0.05).

Short-term ischemia-reperfusion in trained men results in a modest and transient increase in selected blood oxidative stress biomarkers. Oral GPLC supplementation does not attenuate the increase in these biomarkers.