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The aim of this study was to investigate whether exercise stress (short [2 h] or prolonged [5 h] forced swimming in rats) could modulate brain total antioxidant status (TAS), tissue protein concentration, and the activities of acetylcholinesterase (AChE), Na +, K +-ATPase, and Mg 2+-ATPase. Protein concentration, TAS and enzyme activities in homogenized rat brain were determined spectrophotometrically. Protein concentration was decreased by 15 % (p < 0.01) and by 30 % (p < 0.001) after 2 h and 5 h of forced swimming, respectively. TAS was decreased by 20 - 25 % after 2 h or 5 h of exercise. AChE was inhibited by 30 % (p < 0.001) and 45 % (p < 0.001) after 2 h and 5 h of forced swimming, respectively. In contrast, Na +, K +-ATPase and Mg 2+-ATPase were stimulated by 80 % (p < 0.001) and 40 % (p < 0.001), respectively, after 2 h of swimming and by 100 % (p < 0.001) and 60 % (p < 0.001), respectively, after 5 h of exercise. Control values in nontreated rats were unaltered (p > 0.05). In conclusion, short or prolonged forced swimming induces oxidative stress in rats, probably resulting in a reduction in brain protein concentration and AChE activity. In addition, a Na +, K +-ATPase and Mg 2+-ATPase activation was observed under the above mentioned experimental conditions. This stress condition may modulate brain intracellular Mg 2+ concentration, neural excitability, metabolic energy production, and neurotransmission.

The activity of lecithin: cholesterol acyltransferase (LCAT) and the plasma lipoprotein concentrations of elite athletes from 8 selected sports (volleyball, judo, sprinting, wrestling, throwing, cycling, water polo and tennis) were determined and compared with those of a sedentary control group. Plasma LCAT activity levels in the athletes were significantly 2.2-7.0 times higher than in the controls in most sports (p less than 0.01). Judo, sprinting, wrestling and throwing had comparable LCAT values while tennis, volleyball and cycling were considerably higher. HDL-C concentration was significantly higher than controls in the water polo (p less than 0.05), cycling and volleyball (p less than 0.01) groups. Percentage lipoprotein distribution in the athletes in all sports except tennis, throwing and wrestling were similar to the controls. The differences among groups in LCAT activity may be related to the effect of physical exercise and training adaptations to lipid metabolism. This may be of importance when judging the benefit of exercise for atherosclerosis protection.

The aim of this work was to obtain an insight into the influence exerted upon plasma lipid parameters by high quality physical training in different specialties of nine Olympic sports. We compared the concentrations of serum cholesterol (TC), total lipids (TL), triglycerides (TG), HDL, LDL, VLDL, and % distribution of HDL, LDL, and VLDL of elite athletes (n = 127, age = 22.0 +/- 3.2 yrs) participating in regular training for over 3 years (2-4 h/day), separated into 11 groups of athletic specialties, with those obtained from a group of selected sedentary controls (n = 26, age = 25.3 +/- 4.5 yrs). We also compared the lipoprotein ratio factor (RF) values TC/HDL and LDL/HDL. The athletic disciplines examined were football, basketball, volleyball, boxing, wrestling, judo, sailing, skiing (slalom), track (two groups), and throwing-jumping. Football, volleyball, judo, SD and LD running, and the total sum of athletes had significantly higher HDL than the controls. Football, basketball, volleyball and all the disciplines taken together showed significantly lower LDL. Boxing, judo, and LD running had significantly lower VLDL and volleyball, SD, and LD running significantly lower %VLDL. Volleyball had significantly lower TL, boxing and volleyball lower TC, while judo, boxing, SD and LD running had lower TG. Sailing had significantly lower %HDL and higher %LDL and TL than the controls; wrestling, skiing, and throwing-jumping did not differ. In all the athletes taken together, VO2 max or relative body weight, with respect to HDL and TC/HDL, were found to be slightly correlated (r = 0.30, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)