title: Lactate and Energy Metabolism During Exercise in Patients With Blocked Glycogenolysis (McArdle Disease).
abstract: BACKGROUND
  Patients with blocked muscle glycogen breakdown (McArdle disease) have severely reduced exercise capacity compared to healthy individuals and are not assumed to produce lactate during exercise.
  
  
  OBJECTIVE
  The objectives were: 1) to quantify systemic and muscle lactate kinetics and oxidation rates and muscle energy utilization during exercise in patients with McArdle disease; and 2) to elucidate the role of lactate formation in muscle energy production.
  
  
  METHODS
  This was a single trial in a hospital.
  
  
  METHODS
  Participants were four patients with McArdle disease and seven healthy subjects.
  
  
  METHODS
  Patients and healthy controls were studied at rest, which was followed by 40 minutes of cycle-ergometer exercise at 60% of the patients' maximal oxygen uptake (∼35 W).
  
  
  METHODS
  Main outcome measures were systemic and leg skeletal muscle lactate, alanine, fatty acid, and glucose kinetics.
  
  
  RESULTS
  McArdle patients had a marked decrease in plasma lactate concentration at the onset of exercise, and the concentration remained suppressed during exercise. A substantial leg net lactate uptake and subsequent oxidation occurred over the entire exercise period in patients, in contrast to a net lactate release or no exchange in the healthy controls. Despite a net lactate uptake by the active leg, a simultaneous unidirectional lactate release was observed in McArdle patients at rates that were similar to the healthy controls.
  
  
  CONCLUSIONS
  Lactate is an important energy source for contracting skeletal muscle in patients with myophosphorylase deficiency. Although McArdle patients had leg net lactate consumption, a simultaneous release of lactate was observed at rates similar to that found in healthy individuals exercising at the same very low workload, suggesting that lactate formation is mandatory for muscle energy generation during exercise.
authors.affiliation: Neuromuscular Research Unit, Department of Neurology (M.C.O., T.D.J., S.H., N.P., J.V.), Copenhagen Muscle Research Center (M.C.O., T.D.J., S.H., N.P., J.V., G.H.), and Clinical Metabolomics Core Facility (G.H.), Rigshospitalet, DK-2100 Copenhagen, Denmark; Department of Biomedical Sciences (G.H.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark; Neuromuscular Center (T.T., K.H., R.G.H.), Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, and the Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas 75235; and Department of Neurology (R.G.H.), North Texas VA Medical Center, Dallas, Texas 75216.
authors.forename: Mette Cathrine
authors.initials: MC
authors.lastname: Ørngreen
authors.affiliation: Neuromuscular Research Unit, Department of Neurology (M.C.O., T.D.J., S.H., N.P., J.V.), Copenhagen Muscle Research Center (M.C.O., T.D.J., S.H., N.P., J.V., G.H.), and Clinical Metabolomics Core Facility (G.H.), Rigshospitalet, DK-2100 Copenhagen, Denmark; Department of Biomedical Sciences (G.H.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark; Neuromuscular Center (T.T., K.H., R.G.H.), Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, and the Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas 75235; and Department of Neurology (R.G.H.), North Texas VA Medical Center, Dallas, Texas 75216.
authors.forename: Tina Dysgaard
authors.initials: TD
authors.lastname: Jeppesen
authors.affiliation: Neuromuscular Research Unit, Department of Neurology (M.C.O., T.D.J., S.H., N.P., J.V.), Copenhagen Muscle Research Center (M.C.O., T.D.J., S.H., N.P., J.V., G.H.), and Clinical Metabolomics Core Facility (G.H.), Rigshospitalet, DK-2100 Copenhagen, Denmark; Department of Biomedical Sciences (G.H.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark; Neuromuscular Center (T.T., K.H., R.G.H.), Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, and the Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas 75235; and Department of Neurology (R.G.H.), North Texas VA Medical Center, Dallas, Texas 75216.
authors.forename: Tanja
authors.initials: T
authors.lastname: Taivassalo
authors.affiliation: Neuromuscular Research Unit, Department of Neurology (M.C.O., T.D.J., S.H., N.P., J.V.), Copenhagen Muscle Research Center (M.C.O., T.D.J., S.H., N.P., J.V., G.H.), and Clinical Metabolomics Core Facility (G.H.), Rigshospitalet, DK-2100 Copenhagen, Denmark; Department of Biomedical Sciences (G.H.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark; Neuromuscular Center (T.T., K.H., R.G.H.), Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, and the Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas 75235; and Department of Neurology (R.G.H.), North Texas VA Medical Center, Dallas, Texas 75216.
authors.forename: Simon
authors.initials: S
authors.lastname: Hauerslev
authors.affiliation: Neuromuscular Research Unit, Department of Neurology (M.C.O., T.D.J., S.H., N.P., J.V.), Copenhagen Muscle Research Center (M.C.O., T.D.J., S.H., N.P., J.V., G.H.), and Clinical Metabolomics Core Facility (G.H.), Rigshospitalet, DK-2100 Copenhagen, Denmark; Department of Biomedical Sciences (G.H.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark; Neuromuscular Center (T.T., K.H., R.G.H.), Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, and the Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas 75235; and Department of Neurology (R.G.H.), North Texas VA Medical Center, Dallas, Texas 75216.
authors.forename: Nicolai
authors.initials: N
authors.lastname: Preisler
authors.affiliation: Neuromuscular Research Unit, Department of Neurology (M.C.O., T.D.J., S.H., N.P., J.V.), Copenhagen Muscle Research Center (M.C.O., T.D.J., S.H., N.P., J.V., G.H.), and Clinical Metabolomics Core Facility (G.H.), Rigshospitalet, DK-2100 Copenhagen, Denmark; Department of Biomedical Sciences (G.H.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark; Neuromuscular Center (T.T., K.H., R.G.H.), Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, and the Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas 75235; and Department of Neurology (R.G.H.), North Texas VA Medical Center, Dallas, Texas 75216.
authors.forename: Katja
authors.initials: K
authors.lastname: Heinicke
authors.affiliation: Neuromuscular Research Unit, Department of Neurology (M.C.O., T.D.J., S.H., N.P., J.V.), Copenhagen Muscle Research Center (M.C.O., T.D.J., S.H., N.P., J.V., G.H.), and Clinical Metabolomics Core Facility (G.H.), Rigshospitalet, DK-2100 Copenhagen, Denmark; Department of Biomedical Sciences (G.H.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark; Neuromuscular Center (T.T., K.H., R.G.H.), Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, and the Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas 75235; and Department of Neurology (R.G.H.), North Texas VA Medical Center, Dallas, Texas 75216.
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Haller
authors.affiliation: Neuromuscular Research Unit, Department of Neurology (M.C.O., T.D.J., S.H., N.P., J.V.), Copenhagen Muscle Research Center (M.C.O., T.D.J., S.H., N.P., J.V., G.H.), and Clinical Metabolomics Core Facility (G.H.), Rigshospitalet, DK-2100 Copenhagen, Denmark; Department of Biomedical Sciences (G.H.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark; Neuromuscular Center (T.T., K.H., R.G.H.), Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, and the Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas 75235; and Department of Neurology (R.G.H.), North Texas VA Medical Center, Dallas, Texas 75216.
authors.forename: John
authors.initials: J
authors.lastname: Vissing
authors.affiliation: Neuromuscular Research Unit, Department of Neurology (M.C.O., T.D.J., S.H., N.P., J.V.), Copenhagen Muscle Research Center (M.C.O., T.D.J., S.H., N.P., J.V., G.H.), and Clinical Metabolomics Core Facility (G.H.), Rigshospitalet, DK-2100 Copenhagen, Denmark; Department of Biomedical Sciences (G.H.), Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark; Neuromuscular Center (T.T., K.H., R.G.H.), Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, and the Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas 75235; and Department of Neurology (R.G.H.), North Texas VA Medical Center, Dallas, Texas 75216.
authors.forename: Gerrit
authors.initials: G
authors.lastname: van Hall
mesh_terms: D000328:Adult; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006012:Glycogen Storage Disease Type V / Q000378:metabolism*; D050261:Glycogenolysis / Q000502:physiology; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology; D055815:Young Adult
chemical_list: D019344:Lactic Acid