title: Effects of high-intensity intermittent swimming on PGC-1alpha protein expression in rat skeletal muscle.
abstract: OBJECTIVE
  The aim of the present investigation was to elucidate the effects of exercise intensity on exercise-induced expression of peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) protein in rat skeletal muscle.
  
  
  METHODS
  We measured PGC-1alpha content in the skeletal muscles of male Sprague-Dawley rats (age: 5-6 weeks old; body weight: 150-170 g) after a single session of high-intensity intermittent exercise (HIE) or low-intensity prolonged swimming exercise (LIE). During HIE, the rats swam for fourteen 20-s periods carrying a weight (14% of body weight), and the periods of swimming were separated by a 10-s pause. LIE rats swam with no load for 6 h in two 3-h sessions, separated by 45 min of rest.
  
  
  RESULTS
  After HIE, the PGC-1alpha protein content in rat epitrochlearis muscle had increased by 126, 140 and 126% at 2, 6 and 18 h, respectively, compared with that of the age-matched sedentary control rats' muscle. Immediately, 6 and 18-h after LIE, the PGC-1alpha protein content in the muscle was significantly elevated by 84, 95 and 67% respectively. The PGC-1alpha protein content observed 6 h after HIE tended to be higher than that observed after LIE. However, there was no statistically significant difference between the two values (P = 0.12).
  
  
  CONCLUSIONS
  The present investigation suggests that irrespective of the intensity of the exercise, PGC-1alpha protein content in rat skeletal muscle increases to a comparable level when stimuli induced by different protocols are saturated. Further, HIE is a potent stimulus for enhancing the expression of PGC-1alpha protein, which may induce mitochondrial biogenesis in exercise-activated skeletal muscle.
authors.affiliation: Division of Health Promotion and Exercise, Incorporated Administrative Agency, National Institute of Health and Nutrition, Toyama, Shinjuku City, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Terada
authors.forename: K
authors.initials: K
authors.lastname: Kawanaka
authors.forename: M
authors.initials: M
authors.lastname: Goto
authors.forename: T
authors.initials: T
authors.lastname: Shimokawa
authors.forename: I
authors.initials: I
authors.lastname: Tabata
mesh_terms: D000263:Adenylate Kinase / Q000378:metabolism; D000818:Animals; D006003:Glycogen / Q000032:analysis; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism*; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D016601:RNA-Binding Proteins / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013550:Swimming / Q000502:physiology*; D014157:Transcription Factors / Q000032:analysis*
chemical_list: D009124:Muscle Proteins; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C501429:Ppargc1a protein, rat; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D006003:Glycogen; D000263:Adenylate Kinase