title: Effect of acute exercise on monocarboxylate transporters 1 and 4 in untrained and trained Thoroughbreds.
abstract: 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.
  
  
  METHODS
  12 Thoroughbreds (6 males and 6 females; age, 3 to 4 years).
  
  
  METHODS
  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
  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.
authors.affiliation: Department of Sports Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Kitaoka
authors.forename: Yukari
authors.initials: Y
authors.lastname: Endo
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Mukai
authors.forename: Hiroko
authors.initials: H
authors.lastname: Aida
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hiraga
authors.forename: Tohru
authors.initials: T
authors.lastname: Takemasa
authors.forename: Hideo
authors.initials: H
authors.lastname: Hatta
mesh_terms: D000818:Animals; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D006736:Horses / Q000502:physiology*; D008297:Male; D027501:Monocarboxylic Acid Transporters / Q000378:metabolism*; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013997:Time Factors
chemical_list: D027501:Monocarboxylic Acid Transporters; D009124:Muscle Proteins; D012333:RNA, Messenger