Effects of dietary essential fatty acids on active thermogenin content in rat brown adipose tissue.
Rats were fed diets providing either 0.3% (low EFA), 3% (control) or 10% (high EFA) of the energy as essential fatty acids. (All diets provided 20 energy percent of fat.) Both the experimental groups had a lower body weight than the controls. Small differences were found between the groups in many traditional parameters of brown adipose tissue activity (wet weight, protein content, mitochondrial content, cytochrome c oxidase activity). A specific increase in the mitochondrial concentration of the 32,000-dalton GDP-binding protein thermogenin was observed in the high EFA group (from 0.30 to 0.45 nmol/mg). When the thermogenin content of the animal was expressed per gram body weight, the content was more than doubled (from 22 to 47 pmol/g body weight) in the high EFA group, but was unaltered in the low EFA group. It is concluded that the effect of low EFA is nonspecific and due to a general decrease in health status. The effects of high EFA are, however, specific and resemble the changes observed in animals exhibiting diet-induced thermogenesis. It is suggested that the animals fed high amounts of essential fatty acids are in a state of decreased metabolic efficiency and this may be at least in part an explanation for their low body weight.
D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D004041:Dietary Fats / Q000008:administration & dosage*; D003576:Electron Transport Complex IV / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects; D005228:Fatty Acids, Essential / Q000008:administration & dosage*; D019204:GTP-Binding Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins; D008970:Molecular Weight; D010455:Peptides / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism*; D000071256:Uncoupling Protein 1
D002352:Carrier Proteins; D004041:Dietary Fats; D005228:Fatty Acids, Essential; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D010455:Peptides; D011956:Receptors, Cell Surface; D000071256:Uncoupling Protein 1; D003576:Electron Transport Complex IV; D019204:GTP-Binding Proteins