Suplementação de cetoanálogos como quelante nas concentracões sanguíneas elevadas de amônia durante exercício prolongado e dieta cetogênica

Abstract

Ammonia (here used as a synonym for NH3 + NH4+) is a toxic metabolite with deleterious effects on the central nervous system. Exercise can be used as a model to study ammonia metabolism and hyperammonemia. The temporary disturbances in the central nerve system caused by exercise are similar to the observed in hepatic disease and neurodegenerative disorders. Increase of adenosine monophosphate (AMP) during prolonged exercise leads to an production of inosine monophosphate (IMP). Furthermore, amino acids are used as carbon donors for the tricarboxylic acid cycle to maintain the ATP concentration in the cell. Both metabolic pathways lead to an increase in intracellular and ammonemia concentration. In these events, the blood ammonia concentration can raise up to 400% the resting levels. Changes in ammonia levels in response to exercise can be managed through the use of amino acids or carbohydrates that interfere with the metabolism of ammonia. Low carbohydrates diet (called here as ketogenic diet) combined with physical exercise can reduce glycogen stores, inducing early states of hyperammonemia. We explored the ability of a ketogenic diet to enhance the effect of exercise on ammonia production. Though, keto analogues can serve as a nutritional supplement to provide amino acids of high biological value, as well as a tool for ammonia sequestering. In the present study, we used exercise stress to investigate ammonia metabolism. We studied a low-carbohydrate ketogenic diet and exercise as a hyperammonemia model in order to understand the role of the association of keto analogues and amino acid (KAAA) supplementation in ammonia metabolism.