Effects of Taurine Administration on Carbohydrate Metabolism in Skeletal Muscle during the Post-Exercise Phase

Abstract

We previously reported that taurine (2-aminoethanesulfonic acid; dose: 0.5 mg/g body weight) administration after treadmill running at 25 m/min for 90 min increased the glycogen concentration in the skeletal muscle of ICR mice at 120 min after the exercise (Takahashi et al. 2014). In the current study, we further investigated the effects of taurine administration on glycogen repletion and carbohydrate metabolism in the tibialis anterior muscle after endurance exercise. The metabolomic profiles of the tibialis anterior muscle at 120 min after the exercise were analyzed by a capillary electrophoresis-time-of-flight mass spectrometry (n=6). Fructose-1,6-bisphosphate (F1,6P), a glycogenolytic/glycolytic intermediate produced by phosphofructokinase, was significantly lower in the taurine-treated group than that in the control group (p<0.01). Dihydroxyacetonephosphate (DHAP), a downstream product of F1,6P was lower (p=0.05) and glycerol 3-phosphate, a downstream product of F1,6P and DHAP, tended to be lower (p=0.09) in the taurine-treated group than in the controls. At that time, phosphorylated Ser²⁹³ on the E1α subunit of pyruvate dehydrogenase (PDH) tended to be higher in the taurine-treated mice than in the controls (p=0.09, n=5). There was a positive correlation between phosphorylation of the PDH E1α subunit at Ser²⁹³ and glycogen concentration (r=0.73, p<0.05). Our results showed that the enhanced glycogen repletion in skeletal muscle by taurine treatment during the post-exercise phase was accompanied by the lower levels of glycogenolytic/glycolytic intermediates.