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Effect of acute exercise on monocarboxylate transporters 1 and 4 in untrained and trained Thoroughbreds
- Kitaoka, Yu, Endo, Yukari, Mukai, Kazutaka, Aida, Hiroko, Hiraga, Atsushi, Takemasa, Tohru, Hatta, Hideo
- American journal of veterinary research 2013 v.74 no.4 pp. 642-647
- Thoroughbred, biopsy, exercise, exercise test, females, gene expression, gene expression regulation, horses, males, messenger RNA, muscles, oxygen consumption, protein content, transporters
- Objective-To evaluate the effects of a single incremental exercise test (IET) on mRNA expression and protein content of monocarboxylate transporter (MCT) 1 and MCT4 in the gluteus medius muscle of Thoroughbreds. Animals-12 Thoroughbreds (6 males and 6 females; age, 3 to 4 years). Procedures-Horses underwent an IET before and after 18 weeks of high-intensity exercise training (HIT). Horses were exercised at 90% of maximal oxygen consumption for 3 minutes during the initial 10 weeks of HIT and 110% of maximal oxygen consumption for 3 minutes during the last 8 weeks of HIT. Gluteus medius muscle biopsy specimens were obtained from horses before (baseline), immediately after, and at 3, 6, and 24 hours after the IET. Results-Expression of MCT1 and MCT4 mRNA was upregulated at 3 and 6 hours after the IET in muscle specimens obtained from horses prior to HIT (untrained horses) and at 6 hours after the IET in muscle specimens obtained from horses after HIT (trained horses). For both untrained and trained horses, MCT1 and MCT4 protein contents were increased at 6 hours after the IET and did not differ at 24 hours after the IET, compared with those at baseline. Conclusions and Clinical Relevance-Results indicated that a single IET resulted in transient increases in MCT1 and MCT4 mRNA expression and protein content in untrained and trained horses. These results may be important for the elucidation of exercise-induced alterations in lactate metabolism.