Abstract des Autors

This study investigated the effects of pre-exercise branched-chain amino acid (BCAA) administration on blood ammonia levels and on time to exhaustion during treadmill exercise in rats. Adult female Wistar rats were trained on a motor driven treadmill. After a 25-h fast, rats were injected intraperitoneally (i.p.) with 1 mL of placebo or BCAA (30 mg), 5 min before performing 30 min of submaximal exercise (N=18) or running to exhaustion (N=12). In both cases, rats were sacrificed immediately following exercise, and blood was collected for the measurement of glucose, nonesterified fatty acid (NEFA), lactic acid, BCAA, ammonia, and free-tryptophan (free-TRP) levels. Control values were obtained from sedentary rats that were subjected to identical treatments and procedures (N=30). Plasma BCAA levels increased threefold within 5 min after BCAA administration. Mean run time to exhaustion was significantly longer after BCAA administration (99+/-9 min) compared with placebo (76+/-4 min). During exercise, blood ammonia levels were significantly higher in the BCAA treated compared with those in the placebo treated rats both in the 30-min exercise bout (113+/-25 micro-mol/L (BCAA) vs 89+/-16 micro-mol/L) and following exercise to exhaustion (186+/- 44 micro-mol/L (BCAA) vs 123+/-19 micro-mol/L). These data demonstrate that BCAA administration in rats results in enhanced endurance performance and an increase in blood ammonia during exercise. Verf.-Referat