Participation of blood cells in the changes of blood amino acid concentrations during maximal exercise.

We determined the participation of the cellular compartment in the changes of plasma amino acid concentrations during maximal exercise test on a cycle ergometer. Following an overnight fast, male athletes were submitted to a maximal exercise test until fatigue (for 25 min approximately) to determine maximal oxygen uptake. The amino acid concentrations in total blood, plasma, and blood cells were determined before and after the maximal exercise test. Most essential amino acids were decreased significantly in the total blood concentration as a result of the maximal exercise test. However, the concentrations of most nonessential amino acids tended to be significantly increased. Amino acid concentration was increased most in plasma. Concentrations of blood cell alanine and proline were significantly increased by 26% and 15%, respectively, after the maximal exercise test. No significant differences in blood cell concentrations of other amino acids induced by the exercise test were found, although the amount of tryptophan in blood cells was increased after exhaustive exercise.

Regulation of erythrocyte antioxidant enzyme activities in athletes during competition and short-term recovery.

We have determined "in vivo" the influence of strenuous prolonged exercise and short-term recovery on erythrocyte antioxidant enzyme activities. We have also determined the "in vitro" effects of the xanthine/xanthine-oxidase-generating superoxide anion system on catalase activity in haemolysed erythrocytes. Haematological parameters and erythrocyte superoxide dismutase (SOD), glutathione peroxidases and catalase activities were measured in nine healthy duathlon athletes under basal conditions, at the finish of a competition and after 1 h of recovery. We also measured catalase activity in haemolysed erythrocytes--obtained from four overnight-fasted well-trained sportsmen before and after an 80% submaximal exercise test on a cycle-ergometer--prior to and after incubation for 3 min with the superoxide-anion-generating system. Duathlon competition and/or short-term recovery produced a slight haemolysis and increased the activity of catalase and peroxidases but not SOD enzymes. The observed changes in catalase activity were mimicked "in vitro" by the superoxide-anion-generating system.