title: Combined effects of hypoxia and endurance training on lipid metabolism in rat skeletal muscle.
abstract: OBJECTIVE
  To determine whether endurance training can counterbalance the negative effects of hypoxia on mitochondrial phosphorylation and expression of the long chain mitochondrial fatty acid transporter muscle carnitine palmitoyl transferase 1 (mCPT-1).
  
  
  METHODS
  Male Wistar rats were exposed either to hypobaric hypoxia (at a simulated altitude of approximately 4000 m, PIO(2) approximately 90 mmHg) or to normoxia (sea level) for 5 weeks. In each environment, rats were randomly assigned to two groups. The trained group went through a 5-week endurance training programme. The control group remained sedentary for the same time period. Muscle fatty acid oxidation capacity was evaluated after the 5-week period on isolated mitochondria prepared from quadriceps muscles with the use of palmitoylcarnitine or pamitoylCoA + carnitine.
  
  
  RESULTS
  Chronic hypoxia decreased basal (V(0), -31% with pamitoylCoA + carnitine and -21% with palmitoylcarnitine, P < 0.05) and maximal (V(max), -31% with pamitoylCoA + carnitine, P < 0.05) respiration rates, hydroxyacylCoA dehydrogenase activity (-48%, P < 0.05), mCPT-1 activity index (-34%, P < 0.05) and mCPT-1 protein content (-34%, P < 0.05). Five weeks of endurance training in hypoxia brought V(0), mCPT-1 activity index and mCPT-1 protein content values back to sedentary normoxic levels. Moreover, in the group trained in hypoxia, V(max) reached a higher level than in the group that maintained a sedentary lifestyle in normoxia (24.2 nmol O(2). min(-1) . mg(-1) for hypoxic training vs. 19.9 nmol O(2) . min(-1) . mg(-1) for normoxic sedentarity, P < 0.05).
  
  
  CONCLUSIONS
  Endurance training can attenuate chronic hypoxia-induced impairments in mitochondrial fatty acid oxidation. This training effect seems mostly mediated by mCPT-1 activity rather than by mCPT-1 content.
authors: UMR 866, Différenciation Cellulaire et Croissance, INRA, Université Montpellier 1, Montpellier, France. olivier.galbes@hotmail.fr
authors: O
authors: O
authors: Galbès
authors: L
authors: L
authors: Goret
authors: C
authors: C
authors: Caillaud
authors: J
authors: J
authors: Mercier
authors: P
authors: P
authors: Obert
authors: R
authors: R
authors: Candau
authors: G
authors: G
authors: Py
mesh_terms: D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000378:metabolism; D000531:Altitude; D000818:Animals; D001835:Body Weight; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism; D019069:Cell Respiration; D002908:Chronic Disease; D002950:Citrate (si)-Synthase / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism*; D050356:Lipid Metabolism; D008297:Male; D008931:Mitochondria, Muscle / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D010084:Oxidation-Reduction; D010805:Physical Conditioning, Animal / Q000379:methods / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D005227:Fatty Acids; D006454:Hemoglobins; D015094:3-Hydroxyacyl CoA Dehydrogenases; D002334:Carnitine O-Palmitoyltransferase; D002950:Citrate (si)-Synthase