title: Effects of individual fatty acids on glucose uptake and glycogen synthesis in soleus muscle in vitro.
abstract: Soleus muscle strips from Wistar rats were preincubated with palmitate in vitro before the determination of insulin-mediated glucose metabolism in fatty acid-free medium. Palmitate decreased insulin-stimulated glycogen synthesis to 51% of control in a time- (0-6 h) and concentration-dependent (0-2 mM) manner. Basal and insulin-stimulated glucose transport/phosphorylation also decreased with time, but the decrease occurred after the effect on glycogen synthesis. Preincubation with 1 mM palmitate, oleate, linoleate, or linolenate for 4 h impaired glycogen synthesis stimulated with a submaximal physiological insulin concentration (300 microU/ml) to 50-60% of the control response, and this reduction was associated with impaired insulin-stimulated phosphorylation of protein kinase B (PKB). Preincubation with different fatty acids (all 1 mM for 4 h) had varying effects on insulin-stimulated glucose transport/phosphorylation, which was decreased by oleate and linoleate, whereas palmitate and linolenate had little effect. Across groups, the rates of glucose transport/phosphorylation correlated with the intramuscular long-chain acyl-CoA content. The similar effects of individual fatty acids on glycogen synthesis but different effects on insulin-stimulated glucose transport/phosphorylation provide evidence that lipids may interact with these two pathways via different mechanisms.
authors.affiliation: Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia. a.thompson@garvan.unsw.edu.au
authors.forename: A L
authors.initials: AL
authors.lastname: Thompson
authors.forename: M Y
authors.initials: MY
authors.lastname: Lim-Fraser
authors.forename: E W
authors.initials: EW
authors.lastname: Kraegen
authors.forename: G J
authors.initials: GJ
authors.lastname: Cooney
mesh_terms: D000214:Acyl Coenzyme A / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004041:Dietary Fats / Q000494:pharmacology; D005227:Fatty Acids / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism*; D019298:Glucose-6-Phosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006003:Glycogen / Q000096:biosynthesis*; D066298:In Vitro Techniques; D007328:Insulin / Q000502:physiology; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000214:Acyl Coenzyme A; D004041:Dietary Fats; D005227:Fatty Acids; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D011518:Proto-Oncogene Proteins; C015785:2-deoxyglucose-6-phosphate; D019298:Glucose-6-Phosphate; D000255:Adenosine Triphosphate; D006003:Glycogen; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D005947:Glucose