Acute exercise increases monocarboxylate transporter 2 expression in mouse cerebellum

Abstract

It is known that lactate is an oxidizable substrate for metabolic tissues. Monocarboxylate transporter (MCT), a membrane protein, facilitates membrane transport of lactate. MCT1 and MCT2 are main lactate transporters in brain. It was shown that exercise increases acutely MCTs expression in muscles but it is not known in brain. The purpose of this study is to examine whether acute exercise can increase MCT mRNA and protein levels in brain. 8‐wk‐old ICR male mice were randomly divided into there groups, which is pre‐exercise (PRE), 0 h (0h) or 5 h (5h) after 6 h of treadmill running. Except for the PRE group, the mice completed 6 h treadmill running (20 m/min) in which the exercise session consisted of two 3 h of bouts separated by 30 min of rest. Cerebral cortex and cerebellum were rapidly harvested at each sampling time. MCT1 and MCT2 mRNA abundances in cerebral cortex were not altered after 6 h of treadmill running. Conversely, MCT2 mRNA in cerebellum, but not MCT1, was significantly increased by 113% (p<0.05) at 5 h after the exercise. MCT1 and MCT2 protein contents were not altered after the exercise in cerebral cortex and cerebellum, either. These findings suggest that MCT2 in cerebellum may have a key role to maintain energy supply to cerebellum during exercise, but a single bout of exercise was not sufficient to increase the protein in MCT2 of cerebellum.