title: High-fat diet impairs the effects of a single bout of endurance exercise on glucose transport and insulin sensitivity in rat skeletal muscle.
abstract: A single bout of exercise increases the rate of muscle glucose transport (GT) by both insulin-independent and insulin-dependent mechanisms. The purpose of this study was to determine whether high-fat diet (HFD) feeding interferes with the metabolic activation induced by moderate-intensity endurance exercise. Rats were fed an HFD or control diet (CD) for 4 weeks and then exercised on a treadmill for 1 hour (19 m/min, 15% incline). Insulin-independent GT was markedly higher in soleus muscle dissected immediately after exercise than in muscle dissected from sedentary rats in both dietary groups, but insulin-independent GT was 25% lower in HFD-fed than in CD-fed rats. Insulin-dependent GT in the presence of submaximally effective concentration of insulin (0.9 nmol/L) was also higher in both dietary groups in muscle dissected 2 hours after exercise, but was 25% lower in HFD-fed than in CD-fed rats. Exercise-induced activation of 5'adenosine monophosphate-activated protein kinase, a signaling intermediary leading to insulin-independent GT and regulating insulin sensitivity, was correspondingly blunted in the HFD group. High-fat diet did not affect glucose transporter 4 content or insulin-stimulated Akt phosphorylation. Our findings provide evidence that an HFD impairs the effects of short-term endurance exercise on glucose metabolism and that exercise does not fully compensate for HFD-induced insulin resistance in skeletal muscle. Although the underlying mechanism is unclear, reduced 5'adenosine monophosphate-activated protein kinase activation during exercise may play a role.
authors.affiliation: Department of Medicine and Clinical Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Satsuki
authors.initials: S
authors.lastname: Tanaka
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hayashi
authors.forename: Taro
authors.initials: T
authors.lastname: Toyoda
authors.forename: Taku
authors.initials: T
authors.lastname: Hamada
authors.forename: Yohei
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Masakazu
authors.initials: M
authors.lastname: Hirata
authors.forename: Ken
authors.initials: K
authors.lastname: Ebihara
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Masuzaki
authors.forename: Kiminori
authors.initials: K
authors.lastname: Hosoda
authors.forename: Tohru
authors.initials: T
authors.lastname: Fushiki
authors.forename: Kazuwa
authors.initials: K
authors.lastname: Nakao
mesh_terms: D000263:Adenylate Kinase / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D004041:Dietary Fats / Q000008:administration & dosage* / Q000378:metabolism; D004789:Enzyme Activation; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D051058:Oncogene Protein v-akt / Q000378:metabolism; D010766:Phosphorylation; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D014280:Triglycerides / Q000378:metabolism
chemical_list: D004041:Dietary Fats; D051275:Glucose Transporter Type 4; C495694:Slc2a4 protein, rat; D014280:Triglycerides; D006003:Glycogen; D051058:Oncogene Protein v-akt; D000263:Adenylate Kinase; D005947:Glucose