[1D3] Exercise training increases MCT expression in STZ-induced diabetic rats

【Purpose】 We investigated the changes of MCT1 and MCT4 protein expression in STZ-induced diabetic rats with or without the exercise training. In addition, we examined plasma membrane content of MCT1 and MCT4 protein by the giant vesicle procedure. 【Methods】 Male Wistar rats (aged 4wks) were randomly assigned to a control (C), trained (Tr), diabetes (D) and trained diabetes (TD) group. Through the 3 weeks with the appropriate treatment (exercise training, induced the diabetes and sedentary), Plantaris (Pla), Soleus (Sol), extensor digitorum longus (EDL) and Heart of all rats were taken and analyzed for MCT1 and MCT4 protein by Western Blotting. Membrane vesicle MCT1 and MCT4 were also measured by Western Blotting. 【Results】 The MCT1 expression in these oxidative fibers (Pla, Sol and Heart) were consistent in each group. To compare with C, there were significant increase in Tr, significant decrease in D and almost the same level in TD. The MCT4 expression in these glycolytic fibers (Pla, Sol and EDL) were also consistent in each group. Membrane vesicles MCT1 and MCT4 expression were significantly decreased in D compared with C. 【Discussion】 We have found that 1) in diabetic condition, MCT1 and MCT4 protein are markedly decreased, but with the exercise training 2) these depletion are inhibited and MCT protein could recovered as a control level and 3) the depletion of MCT protein in diabetic condition are also found in the muscle cell surface (plasma membrane). In the diabetic state, exercise training can impair glucose metabolism and activate lactate flow that is into and out of the skeletal muscle cells. These factors could result in increasing MCT protein expression even in a diabetic state.