Effect of chronic oral supplementation with L-glutamine and L-alanine, in their free forms or as dipeptide, on parameters associated with fatigue in rats submitted to resistance exercise

Abstract

Fatigue is characterized by decline of strength level, intensity and velocity of muscle contraction, affecting physical performance. The amino acids glutamine and alanine are associated with delayed fatigue process, since they are important energy substrates and deliver ammonia to liver and kidneys, reducing accumulation of this toxic metabolite. The aim of this study is to evaluate the effects of chronic supplementation with L-glutamine and L-alanine on the fatigue development. Forty adult male Wistar rats will be randomly distributed in experimental groups: (SED untrained and receiving water) CTRL (trained and receiving water), ALA, GLN + ALA and DIP (trained and supplemented with L-alanine, L-alanine and L-glutamine in their free forms, and as dipeptide, respectively). The experiment will last eight weeks, and the last six weeks intended for resistance training, which consists of climbing a vertical ladder with cargo loading progressively increased (25-100% of body weight). The supplementation will be diluted in a 4% solution and offered orally, ad libitum, in the drinking water of the animals during the last 21 days of training (more intense exercise period). It will be analyzed plasma parameters: lactate, glucose, aminogram, hypoxanthine/xanthine, fatty acids, ammonia, Lactate Dehydrogenase (LDH), Creatine Kinase (CK), malondialdehyde, 8-isoprostane and glutathione; and tissue parameters: serotonin and dopamine in the hypothalamus, glycogen and ammonia (muscle and liver), muscle glutamine, glutamate and alanine, muscle expression of LDH, adenosine monophosphate deaminase enzyme (AMPD1), Citrate Synthase (CS) and monocarboxylate transporter 1 and 4 (MCT1 and MCT4), muscle histology and maximum load tests. (AU)