The effects of endurance training and L-arginine supplementation on nitric oxide production, muscle glycogen concentration, and endurance performance

Abstract

The purpose of this study was to examine the effects of endurance training and prolonged L-arginine supplementation on blood glucose, blood insulin, muscle glycogen, muscle glycogen synthase (GS), muscle nitric oxide (NO), muscle nitric oxide synthase (NOS), endurance performance. We equally divided 36 Sprague-Dawley mice to be distributed into control group, L-NMMA treated group and L-arginine treated group. The L-arginine treated group and L-NMMA treated group consumed 10 mg/kg/day of L-arginine and 5 mg/kg/day of L-NMMA for 6 weeks period. Mice of control group, L-arginine treated group, and L-NMMA treated groups performed swimming exercise training for 60 min once a day, 5 days per week for 6 weeks. Blood glucose had tendency to increase in L-arginine treated group than the control group, and insulin significantly increased in L-arginine treated group than the control group. L-arginine treated group showed significant increase in glycogen, GS, NO and NOS in the gastrocnemius muscle and soleus muscle compared to the control group. Whereas L-NMMA treated group showed the lowest glycogen, GS, NO and NOS in the gastrocnemius muscle and soleus muscle compared to control group and L-arginine treated group. Exhaustive swimming time had tendency to increase in L-arginine treated group compared to the value for control group. These reults indicate that endurance training and prolonged L-arginine supplementation appear to be effective in exhancing nitric oxide production, glycogen concentration and endurance performance.