The effect of soy protein and combination of chromium /amylopectin intake on protein syntesis and mTOR pathways in after exercise in rats

The present study was conducted to investigate the effect of the combination of soy protein, amylopectin and chromium (SAC) on protein synthesis, signal transduction pathways involved in protein synthesis (mTOR pathways, IGF-1 and Akt) and proteolysis (FOXO1; MURF1, MAFbx) in exercised rats. Thirty-five Wistar rats were randomly divided into 5 groups: 1) Control (C); 2) Exercise (E); 3) Exercise+Soy Protein (E+S); 4) Exercise+Soy Protein+Chromium (E+S+Cr) and 5) Exercise+Soy Protein+ Amylopectin +Chromium (E+S+A+Cr). Post-exercise ingestion of SAC significantly increased the fractional rate of protein synthesis (FSR), insülin, glycogen, and amino acid levels with the highest effect observed in E+S+A+Cr group (P˂0.05). However, SAC supplementation decreased the lactic acid concentration (P˂0.05). A reduction in forkhead box protein O1 (FOXO1) and forkhead box protein O3 (FOXO3) (regulators of ubiquitin-related proteolysis) and muscle atrophy F-box (MAFbx) levels was noted after treatment with SAC (P<0.05). Insulin-like growth factor 1(IGF-1) level was increased in the E+S, E+S+Cr and E+S+A+Cr groups (P<0.05). While the phosphorylation of 4E-BP1, Akt, mTOR and S6K1 levels increased after SAC supplementation, phosphorylated muscle ring finger 1 (MuRF-1) was found to be significantly lower compared with the E group (P˂0.05). These results indicate that SAC supplementation improves FSR, insulin and glycogen levels after exercise. SAC improves protein synthesis by inhibiting the ubiquitin-proteasome pathway and inducing anabolic metabolism. Keywords: Soy protein, Amylopectin, Chromium, Protein synthesis, Ubiquitin-proteasome Pathway.