Effect of chronic supplementation with L-glutamine and L-alanine, in free form or as dipeptide, on parameters associated with fatigue in rats subjected to resistance training.

Abstract

The state of fatigue is characterized by declining level of strength, intensity and speed of muscle contraction, which can affect physical performance. The amino acids glutamine and alanine are associated with delayed fatigue process, since they are used as energy substrates and carry ammonia to the liver and kidneys, reducing the toxicity of this metabolite. The aim of this study is to evaluate the effects of chronic supplementation with L-glutamine and L-alanine on the development of fatigue. Forty adult male Wistar rats will be randomly distributed in experimental groups: SED (untrained, receiving water), CTRL (trained, receiving water), ALA, GLN + ALA and DIP (trained and supplemented with L-alanine, L-alanine and L-glutamine in free form and as a dipeptide, respectively). The experiment will last for eight weeks, and the last six weeks will be intended for resistance training, which consists of climbing a vertical ladder, with progressively increased load (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 training period. Will be analyzed plasma parameters: lactate, glycaemia, aminogram, hypoxanthine/xanthine, free fatty acids, ammonia, lactate dehydrogenase (LDH), creatine kinase (CK), malondialdehyde, 8-isoprostane and glutathione; and tissue parameters: serotonin and dopamine hypothalamic levels, glycogen and ammonia (muscle and hepatic), muscle glutamine, glutamate and alanine, muscle expression of LDH enzyme, adenosine monophosphate deaminase (AMPD1), citrate synthase (CS) and monocarboxylate transporter 1 and 4 (MCT1 and MCT4), muscle histology and maximum load tests. (AU)