Effects of a peroxisome proliferator on beta-oxidation and overall energy balance in obese (fa/fa) rats.
The aim of the study was to examine in the obese Zucker (fa/fa) rats the effect of a peroxisome proliferator nafenopin on liver and brown adipose tissue peroxisomal and mitochondrial beta-oxidation enzyme activities and on the overall energy dissipation. A 17-day nafenopin treatment increased liver wet weight 2.1-fold and liver total acyl-CoA oxidase and mitochondria beta-oxidative activities 32- and 4.6-fold, respectively. It increased the interscapular brown adipose tissue (IBAT) acyl-CoA oxidase activity 2.1-fold but had no effect on the mitochondria beta-oxidative activity. Because nafenopin was found to decrease food intake by 22%, obese nafenopin-treated rats were compared with a group of obese pair-fed rats. Both food restriction and nafenopin treatment decreased body weight gain, but a decrease (14%) in fat content was only observed in nafenopin-treated rats. Food restriction of obese rats decreased the mean metabolic rate by 13%, and nafenopin treatment prevented this decrease. Both food restriction and nafenopin treatment decreased the mean daily respiratory quotient (RQ). However, the RQ of nafenopin-treated rats was steadily lower than that of control, whereas that of food-restricted rats was the same as that of control animals during the feeding period and decreased when food supply was exhausted. The increase in liver and IBAT fatty acid beta-oxidative activities may be the cause of the decreased lipid accretion measured in obese rats.
Assimacopoulos-Jeannet
F
F
Laboratoires de Recherches Métaboliques, Geneva, Switzerland.
Moinat
M
M
Muzzin
P
P
Colomb
C
C
Jeanrenaud
B
B
Girardier
L
L
Giacobino
J P
JP
Seydoux
J
J
D000273:Adipose Tissue / Q000473:pathology; D002001:Adipose Tissue, Brown / Q000378:metabolism / Q000648:ultrastructure; D000818:Animals; D001823:Body Composition; D004734:Energy Metabolism / Q000187:drug effects; D008099:Liver / Q000378:metabolism / Q000648:ultrastructure; D008830:Microbodies / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D008928:Mitochondria / Q000378:metabolism; D009255:Nafenopin / Q000494:pharmacology*; D009765:Obesity / Q000378:metabolism* / Q000473:pathology; D010084:Oxidation-Reduction; D051381:Rats; D011924:Rats, Zucker; D012016:Reference Values
D009255:Nafenopin