title: Chronic caloric restriction alters muscle membrane fatty acid content.
abstract: Chronic caloric restriction (CR) has been demonstrated to increase longevity in lower species and studies are ongoing to evaluate its effect in higher species. A consistent metabolic feature of CR is improved insulin sensitivity and lowered lifetime glycemia, yet the mechanism responsible is currently unknown. However, the membrane's physiochemical properties, as determined by phospholipid composition, have been related to insulin action in animal and human studies and CR has been reported to alter membrane lipid content. We evaluated muscle membrane fatty acid content in rodents randomized to CR versus control diets for up to 29 months. CR was observed to increase the membrane content of C22:6 (docosahexaenoate) and to decrease C18:2 content. The membrane lipid content was related to insulin levels but not to parameters assessing glycemic control. This study suggests that membrane lipids, in particular 22:6, may contribute to the variation in insulin sensitivity seen with age.
authors.affiliation: Department of Medicine, University of Vermont College of Medicine, 55A South Park Drive, T249, Colchester, VT 05446, USA. wcefalu@zoo.uvm.edu
authors.forename: W T
authors.initials: WT
authors.lastname: Cefalu
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Wang
authors.forename: A D
authors.initials: AD
authors.lastname: Bell-Farrow
authors.forename: J G
authors.initials: JG
authors.lastname: Terry
authors.forename: W
authors.initials: W
authors.lastname: Sonntag
authors.forename: M
authors.initials: M
authors.lastname: Waite
authors.forename: J
authors.initials: J
authors.lastname: Parks
mesh_terms: D000818:Animals; D002149:Energy Intake; D005227:Fatty Acids / Q000378:metabolism*; D005260:Female; D005508:Food Deprivation / Q000502:physiology*; D051275:Glucose Transporter Type 4; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance; D008136:Longevity / Q000502:physiology; D008560:Membrane Fluidity; D008563:Membrane Lipids / Q000378:metabolism*; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D009124:Muscle Proteins; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D011914:Rats, Inbred BN
chemical_list: D005227:Fatty Acids; D051275:Glucose Transporter Type 4; D007328:Insulin; D008563:Membrane Lipids; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495692:SLC2A4 protein, human; C495694:Slc2a4 protein, rat