Increased levels or disruptions in the metabolism of branched-chain amino acids (BCAA) seem to be related to insulin resistance (IR) and obesity. The step of BCAA metabolism regulated by branched-chain a-ketoacid dehydrogenase complex (BCKD) is essential to BCAA circulating levels maintenance. Its activity is regulated by BCKD kinase (BDK) and phosphatase (BDP), which respectively induces its inhibition and activation. Therefore, changes in BCDK activity may result in BCAA accumulation, which in turn will promote or worsen IR. In parallel, the exercise has been standing out as a treatment for IR, as it induces insulin sensitivity improvement without significant side effects. However, most studies have focused only on the inflammatory component of the impact of exercise on RI.So, there is a gap in the literature regarding the potential exercise effects on BCAA circulating levels or in its metabolism. Thus, this study aims to analyze the effects of acute exercise on BCAA metabolism and its association to insulin signaling in the skeletal muscle of obese Wistar
Six week Wistar rats were divided into three groups, control (Ctl), sedentary fed with high-fat diet (DIO), and exercised fed a high-fat diet (DIO + EXE). To assess BCAA metabolism, and insulin signaling, we performed western blot analysis. For BCAA and adiponectin, we use, respectively, colorimetric and ELISA assays.
As a result, acute physical swimming exercise resulted in an improvement in both glucose and insulin tolerances, along with an increase in serum adiponectin levels. However, it was not able to alter the BCAA catabolism proteins studied and also failed to reduce circulating levels of BCAA.
Taken together, all the results conclude that the alterations of BCAA metabolism do not participate in the effect that the acute exercise exerts on the signaling pathway and insulin sensitivity in the muscle of obese rats.