Abstract

Background: L-Cysteine (L-Cys) is implicated in the reduction of free radical production. The aim of this study was to investigate whether L-Cys supplementation prevents modulation of the activities of erythrocyte membrane acetylcholinesterase (AChE), Na⁺,K⁺-ATPase and Mg²⁺-ATPase induced by free radicals in basketball players during training.

Methods: Blood was obtained from 10 basketball male players before (group A) and after a game (group B) and after 1 week of L-Cys (0.5 g/24 h orally) supplementation before (group C) and after training (group D). Lactate, pyruvate and total antioxidant status (TAS) were measured using commercial kits and the enzyme activities were determined spectrophotometrically.

Results: Both lactate and pyruvate levels remarkably increased after exercise. In contrast, TAS levels significantly decreased in group B, increased in group C and then declined (group D), reaching those of group A. AChE activity was statistically increased post-exercise (3.98±0.04

× mg protein) compared with pre-training (2.90±0.05 × mg protein, p<0.01). Na⁺,K⁺-ATPase activity was also higher post-exercise (1.27±0.05 μmol Pi/h×mg protein) than that pre-exercise (0.58±0.04 μmol Pi/h×mg protein, p<0.001). When the players were supplemented with L-Cys, both AChE and Na⁺,K⁺-ATPase activities remained unaltered post-exercise. Mg²⁺-ATPase activities were unchanged in all groups studied.

Conclusions: L-Cys supplementation may protect the enzyme activities studied against stimulation induced by free radical production during training in athletes by ameliorating their total antioxidant capacity.

Clin Chem Lab Med 2007;45:67–72.