title: Obesity augments the age-induced increase in mitochondrial capacity for H2O2 release in Zucker fatty rats.
abstract: OBJECTIVE
  Mitochondrial dysfunction has been suggested to play a significant role in obesity and insulin resistance. The aim of the present study was to investigate if changes in obesity and insulin resistance were related to similar changes in mitochondrial capacity for hydrogen peroxide release in Zucker diabetic fatty rats and their lean littermates.
  
  
  METHODS
  Thirty-four rats were used in this study. Rats were either lean or obese Zucker rats killed at 5-6 (young) or 12-14 (adults) weeks of age. Mitochondria were isolated from soleus muscles; respiration and release of hydrogen peroxide were determined and related to citrate synthase activity to determine intrinsic mitochondrial function. Mitochondrial-specific super-oxide dismuthase (MnSOD) protein content was determined in isolated mitochondria and muscle homogenate. Catalase protein content was determined in muscle homogenate.
  
  
  RESULTS
  Young lean and obese rats had a higher mitochondrial respiration when using palmitoyl-l-carnitine as substrate compared with adult lean and obese rats. The obese strain had higher mitochondrial hydrogen peroxide release but only in the adult animals. In both lean and obese animals, increased age was associated with increased mitochondrial hydrogen peroxide release. MnSOD tended to be higher in the obese strain in the isolated mitochondria. Regardless of age, catalase protein content was significantly lower in the obese rats.
  
  
  CONCLUSIONS
  This study shows that the augmented increase in obesity and insulin resistance seen in Zucker diabetic fatty rats is associated with increased capacity for mitochondrial hydrogen peroxide release.
authors.affiliation: Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Denmark. mmogensen@sund.ku.dk
authors.forename: M
authors.initials: M
authors.lastname: Hey-Mogensen
authors.forename: J
authors.initials: J
authors.lastname: Jeppesen
authors.forename: K
authors.initials: K
authors.lastname: Madsen
authors.forename: B
authors.initials: B
authors.lastname: Kiens
authors.forename: J
authors.initials: J
authors.lastname: Franch
mesh_terms: D000367:Age Factors; D000375:Aging / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D002374:Catalase / Q000378:metabolism; D019069:Cell Respiration; D004195:Disease Models, Animal; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008931:Mitochondria, Muscle / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D009765:Obesity / Q000097:blood / Q000378:metabolism*; D018384:Oxidative Stress; D010172:Palmitoylcarnitine / Q000378:metabolism; D051381:Rats; D011924:Rats, Zucker; D013482:Superoxide Dismutase / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D001786:Blood Glucose; D002374:Catalase; D006442:Glycated Hemoglobin; D006861:Hydrogen Peroxide; D007328:Insulin; D010172:Palmitoylcarnitine; D013482:Superoxide Dismutase