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Purpose: Acetate is supplied to skeletal muscle as an energy fuel in endurance exercise. Present study evaluated the dynamics of N-acetyltaurine (NAT) that is N-acetylated form of taurine by acetate after endurance exercise in healthy volunteers and rats. Methods: Using LC-MS/MS system, we measured NAT concentration in blood, urine and skeletal muscle before and after endurance exercises. Results: Serum NAT level was significantly increased from immediately after to 4-hour observation after endurance running in human. Urinary NAT excretion was peaked at 10 hours after the exercise. In rats, NAT concentration in soleus was significantly increased correlated with its level in serum after exhausted treadmill running (40 m/min for 40±3 min). Discussion: Although acetate supplied from liver is an energy fuel in skeletal muscle during endurance exercise, it would be disused after endurance exercise. Because excess acetate in mitochondria of skeletal muscle would cause metabolic abnormality through acetyl-CoA accumulation, taurine might have a physiological role to metabolic normalization in recovery period by promotion of excess acetate excretion in urine. [ABSTRACT FROM AUTHOR]

Purpose: Previously, we showed that taurine supplementation attenuates blood glucose decrease during prolonged exercise. In this study, we focused on hepatic gluconeogenesis as a potential mechanism and examined the change in free amino acids (FAA). Methods: Male Fischer 344 rats, 8 wks of age, were randomly assigned into a taurine-supplemented (Tau) group or a non-supplemented control (Con) group. Both groups were further split into a non-exercise group and an exercise group. All rats were euthanatized and the liver and skeletal muscle were immediately collected before or after a 120 min exercise. Results: Taurine supplementation induced increment of G6Pase activity and lowered glycogenic FAA in the liver. After exercise, FAA of skeletal muscle increased in the Con group but did not change in the Tau group. On the other hand, FAA increased in the liver of the Tau group, whereas its increase in the liver of the Con group was limited. Discussion: FAA derived from the skeletal muscle of the Con group increased during exercise, suggesting that it localizes to the liver and accentuates gluconeogenesis. Alternatively, in the Tau group, FAA release from the skeletal muscle and its re-localization to the liver appears to be enhanced, increasing liver FAA. Conclusion: It is possible that maintenance of blood glucose level during prolonged exercise by taurine supplementation is related to increased hepatic gluconeogenesis. [ABSTRACT FROM AUTHOR]

Purpose: We researched the differences in characteristics between delayed onset muscle soreness (DOMS) and immediate onset muscle soreness (IOMS) in specific muscle groups after eccentric exercise and a full-marathon. Methods: In the Experiment 1, we measured DOMS in 9 young males who performed high intensity eccentric exercise specific to the non-dominant upper extremity flexor muscles. In Experiment 2, we measured IOMS in 19 young males and 3 females who participated in a full-marathon. In both experiments, the visual analog scale (VAS), upper arm or femoral circumference (CIR), serum creatine kinase (CK), and lactate dehydrogenase (LDH) levels were measured before exercise, immediately after exercise, and at 1 to 4 days after exercise. Results: In Experiment 1, VAS peaked on day 2, CIR increased immediately and then temporarily decreased on dayl; however, it then increased until day 4. From days 3 to 4, CK and LDH levels increased. In Experiment 2, VAS increased immediately after a full-marathon and peaked on day 1. Circumference immediately decreased after that; however, it recovered by day 2. Serum CK level peaked on day 1 and LDH level increased immediately after that and both levels decreased by day 3. Conclusion: We suggest that muscle soreness and damage after a full-marathon appeared earlier compared with that after eccentric exercise; however, swelling did not occur after a full-marathon. [ABSTRACT FROM AUTHOR]