title: The relationship between monocarboxylate transporters 1 and 4 expression in skeletal muscle and endurance performance in athletes.
abstract: The purpose of this study was to examine the relationship between skeletal muscle monocarboxylate transporters 1 and 4 (MCT1 and MCT4) expression, skeletal muscle oxidative capacity and endurance performance in trained cyclists. Ten well-trained cyclists (mean +/- SD; age 24.4 +/- 2.8 years, body mass 73.2 +/- 8.3 kg, VO(2max) 58 +/- 7 ml kg(-1) min(-1)) completed three endurance performance tasks [incremental exercise test to exhaustion, 2 and 10 min time trial (TT)]. In addition, a muscle biopsy sample from the vastus lateralis muscle was analysed for MCT1 and MCT4 expression levels together with the activity of citrate synthase (CS) and 3-hydroxyacyl-CoA dehydrogenase (HAD). There was a tendency for VO(2max) and peak power output obtained in the incremental exercise test to be correlated with MCT1 (r = -0.71 to -0.74; P < 0.06), but not MCT4. The average power output (P (average)) in the 2 min TT was significantly correlated with MCT4 (r = -0.74; P < 0.05) and HAD (r = -0.92; P < 0.01). The P (average) in the 10 min TT was only correlated with CS activity (r = 0.68; P < 0.05). These results indicate the relationship between MCT1 and MCT4 as well as cycle TT performance may be influenced by the length and intensity of the task.
authors.affiliation: Health and Exercise Science, School of Medical Science, University of New South Wales, The Goodsell Building, Sydney, NSW, 2052, Australia, d.bentley@unsw.edu.au.
authors.forename: David J
authors.initials: DJ
authors.lastname: Bentley
authors.forename: Belle
authors.initials: B
authors.lastname: Roels
authors.forename: Claire
authors.initials: C
authors.lastname: Thomas
authors.forename: Robert
authors.initials: R
authors.lastname: Ives
authors.forename: Jacques
authors.initials: J
authors.lastname: Mercier
authors.forename: Grégoire
authors.initials: G
authors.lastname: Millet
authors.forename: David
authors.initials: D
authors.lastname: Cameron-Smith