Higher Lactate Transporter Protein and Citrate Synthase Activity Following Short-term High-intensity Repetition Training in Mice

Abstract

The purpose of this study was to examine the effects of high-intensity repetition training, consisting of 4 bouts of high-intensity exercise with long rest periods, on lactate metabolism. To achieve this goal, we compared effects of 3 weeks of two different exercise regimes: high-intensity repetition training (4×1 min run at 45-53 m/min with 19 min of recovery=total 36 running bouts of 1 min), and voluntary wheel running activity, which mimics endurance training. To evaluate the effects on lactate metabolism, we measured protein levels of the monocarboxylate transporters (MCT). We also measured citrate synthase activity as a marker of oxidative capacity in working muscle. After 3 weeks of training, repetition training, but not wheel running training, increased the levels of MCT1 protein, which contributes to lactate uptake into skeletal muscle, in soleus (p<0.05) and also muscular citrate synthase activity in tibialis anterior (p<0.05). MCT4 protein, which plays the role in the removal of lactate from muscle, did not change in plantaris or tibialis anterior following either training regime. These data suggest that short-term high-intensity repetition training is effective at increasing MCT1 and mitochondrial oxidative capacity in skeletal muscle compared to running wheel activity.