title: Fat and carbohydrate metabolism during exercise in phosphoglucomutase type 1 deficiency.
abstract: BACKGROUND
  Phosphoglucomutase type 1 (PGM1) deficiency is a rare metabolic myopathy in which symptoms are provoked by exercise.
  
  
  OBJECTIVE
  Because the metabolic block is proximal to the entry of glucose into the glycolytic pathway, we hypothesized that iv glucose could improve the exercise intolerance experienced by the patient.
  
  
  METHODS
  This was an experimental intervention study.
  
  
  METHODS
  The study was conducted in an exercise laboratory.
  
  
  METHODS
  Subjects were a 37-year-old man with genetically and biochemically verified PGM1 deficiency and 6 healthy subjects.
  
  
  METHODS
  Cycle ergometer, peak and submaximal exercise (70% of peak oxygen consumption), and exercise with an iv glucose infusion tests were performed.
  
  
  METHODS
  Peak work capacity and substrate metabolism during submaximal exercise with and without an iv glucose infusion were measured.
  
  
  RESULTS
  Peak work capacity in the patient was normal, as were increases in plasma lactate during peak and submaximal exercise. However, the heart rate decreased 11 beats minute⁻¹, the peak work rate increased 12.5%, and exercise was rated as being easier with glucose infusion in the patient. These results were in contrast to those in the control group, in whom no improvements occurred. In addition, the patient tended to become hypoglycemic during submaximal exercise.
  
  
  CONCLUSIONS
  This report characterizes PGM1 deficiency as a mild metabolic myopathy that has dynamic exercise-related symptoms in common with McArdle disease but no second wind phenomenon, thus suggesting that the condition clinically resembles other partial enzymatic defects of glycolysis. However, with glucose infusion, the heart rate decreased 11 beats min⁻¹, the peak work rate increased 12.5%, and exercise was considered easier by the patient.
authors.affiliation: Neuromuscular Research Unit, Department of Neurology, Rigshospitalet, University of Copenhagen, DK-2100 Copenhagen, Denmark. npreisler@hotmail.com
authors.forename: Nicolai
authors.initials: N
authors.lastname: Preisler
authors.forename: Pascal
authors.initials: P
authors.lastname: Laforêt
authors.forename: Andoni
authors.initials: A
authors.lastname: Echaniz-Laguna
authors.forename: Mette C
authors.initials: MC
authors.lastname: Ørngreen
authors.forename: Evelyne
authors.initials: E
authors.lastname: Lonsdorfer-Wolf
authors.forename: Stephane
authors.initials: S
authors.lastname: Doutreleau
authors.forename: Bernard
authors.initials: B
authors.lastname: Geny
authors.forename: Tanya
authors.initials: T
authors.lastname: Stojkovic
authors.forename: Monique
authors.initials: M
authors.lastname: Piraud
authors.forename: François M
authors.initials: FM
authors.lastname: Petit
authors.forename: John
authors.initials: J
authors.lastname: Vissing
mesh_terms: D000328:Adult; D001642:Bicycling; D050260:Carbohydrate Metabolism; D005080:Exercise Test; D017079:Exercise Tolerance; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism / Q000627:therapeutic use; D006008:Glycogen Storage Disease / Q000097:blood / Q000378:metabolism* / Q000503:physiopathology / Q000628:therapy; D006339:Heart Rate; D006801:Humans; D007003:Hypoglycemia / Q000209:etiology* / Q000517:prevention & control; D007262:Infusions, Intravenous; D019344:Lactic Acid / Q000097:blood / Q000378:metabolism; D050356:Lipid Metabolism; D008297:Male; D009043:Motor Activity; D018482:Muscle, Skeletal / Q000378:metabolism*; D009135:Muscular Diseases / Q000209:etiology* / Q000503:physiopathology; D010101:Oxygen Consumption; D012720:Severity of Illness Index
chemical_list: D019344:Lactic Acid; D005947:Glucose