title: Skeletal muscle monocarboxylate transporter content is not different between black and white runners.
abstract: The superior performance of black African runners has been associated with lower plasma lactate concentrations at sub-maximal intensities compared to white runners. The aim was to investigate the monocarboxylate transporters 1 (MCT1) and MCT4 content in skeletal muscle of black and white runners. Although black runners exhibited lower plasma lactate concentrations after maximum exercise (8.8 +/- 2.0 vs. 12.3 +/- 2.7 mmol l(-1), P < 0.05) and a tendency to be lower at 16 km h(-1) (2.4 +/- 0.7 vs. 3.8 +/- 2.4 mmol l(-1), P = 0.07) than the white runners, there were no differences in MCT1 or MCT4 levels between the two groups. For black and white runners together, MCT4 content correlated significantly with 10 km personal best time (r = -0.74, P < 0.01) and peak treadmill speed (r = 0.88, P < 0.001), but MCT1 content did not. Although whole homogenate MCT content was not different between the groups, more research is required to explain the lower plasma lactate concentrations in black runners.
authors.affiliation: Department of Human Biology, University of Cape Town, UCT/MRC Research Unit for Exercise Science Sports Medicine, PO Box 115, Newlands, Cape Town 7725, South Africa.
authors.forename: Yolande X R
authors.initials: YX
authors.lastname: Harley
authors.forename: Tertius A
authors.initials: TA
authors.lastname: Kohn
authors.forename: Alan
authors.initials: A
authors.lastname: St Clair Gibson
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Noakes
authors.forename: Malcolm
authors.initials: M
authors.lastname: Collins
mesh_terms: D000328:Adult; D044383:Black People; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D027501:Monocarboxylic Acid Transporters / Q000378:metabolism*; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D009124:Muscle Proteins / Q000378:metabolism*; D010807:Physical Endurance / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology; D012420:Running / Q000502:physiology*; D013019:South Africa; D027981:Symporters / Q000378:metabolism*; D044465:White People; D000099233:Monocarboxylate Transport Protein 1
chemical_list: D019344:Lactic Acid; D027501:Monocarboxylic Acid Transporters; D009124:Muscle Proteins; D027981:Symporters; D000099233:Monocarboxylate Transport Protein 1; C406962:SLC16A4 protein, human