title: Calorie restriction influences key metabolic enzyme activities and markers of oxidative damage in distinct mouse liver mitochondrial sub-populations.
abstract: OBJECTIVE
  The purpose of the study was to establish if enzyme activities from key metabolic pathways and levels of markers of oxidative damage to proteins and lipids differed between distinct liver mitochondrial sub-populations, and which specific sub-populations contributed to these differences.
  
  
  METHODS
  Male C57BL/6J mice were fed non-purified diet for one month then separated into two groups, control and calorie-restricted (CR). The two groups were fed semi-purified diet (AIN93G), with the CR group receiving 40% less calories than controls. After two months, enzyme activities and markers of oxidative damage in mitochondria were determined.
  
  
  RESULTS
  In all mitochondrial sub-populations, enzyme activities and markers of oxidative damage, from control and CR groups, showed a pattern of M1>M3>M10. Higher acyl-CoA dehydrogenase (β-oxidation) and β-hydroxybutyrate dehydrogenase (ketogenesis) activities and lower carbonyl and TBARS levels were observed in M1 and M3 fractions from CR mice. ETC enzyme activities did not show a consistent pattern. In the Krebs cycle, citrate synthase and aconitase activities decreased while succinate dehydrogenase and malate dehydrogenase activities increased in the M1 mitochondria from the CR versus control mice.
  
  
  CONCLUSIONS
  CR does not produce uniform changes in enzyme activities or markers of oxidative damage in mitochondrial sub-populations, with changes occurring primarily in the heavy mitochondrial populations. Centrifugation at 10,000 g to isolate mitochondria likely dilutes the mitochondrial populations which show the greatest response to CR. Use of lower centrifugal force (3000 g or lower) may be beneficial for some studies.
authors.affiliation: VM Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA. Electronic address: khagopian@ucdavis.edu.
authors.forename: Kevork
authors.initials: K
authors.lastname: Hagopian
authors.forename: Robert
authors.initials: R
authors.lastname: Soo Hoo
authors.forename: José A
authors.initials: JA
authors.lastname: López-Domínguez
authors.forename: Jon J
authors.initials: JJ
authors.lastname: Ramsey
mesh_terms: D000154:Aconitate Hydratase / Q000378:metabolism; D000818:Animals; D031204:Caloric Restriction; D002950:Citrate (si)-Synthase / Q000378:metabolism; D002952:Citric Acid Cycle / Q000187:drug effects; D045222:Electron Transport Chain Complex Proteins / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008291:Malate Dehydrogenase / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008930:Mitochondria, Liver / Q000201:enzymology* / Q000502:physiology; D018384:Oxidative Stress / Q000502:physiology*; D050050:Protein Carbonylation / Q000187:drug effects; D013385:Succinate Dehydrogenase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D045222:Electron Transport Chain Complex Proteins; D017392:Thiobarbituric Acid Reactive Substances; D007770:L-Lactate Dehydrogenase; D008291:Malate Dehydrogenase; D013385:Succinate Dehydrogenase; D002950:Citrate (si)-Synthase; D000154:Aconitate Hydratase
keywords: Electron transport chain; Krebs cycle; Lipid peroxidation; Protein carbonyls; Reactive oxygen species; TBARS