title: Resistance training enhances components of the insulin signaling cascade in normal and high-fat-fed rodent skeletal muscle.
abstract: Our laboratory recently reported that chronic resistance training (RT) improved insulin-stimulated glucose transport in normal rodent skeletal muscle, owing, in part, to increased GLUT-4 protein concentration (Yaspelkis BB III, Singh MK, Trevino B, Krisan AD, and Collins DE. Acta Physiol Scand 175: 315-323, 2002). However, it remained to be determined whether these improvements resulted from alterations in the insulin signaling cascade as well. In addition, the possibility existed that RT might improve skeletal muscle insulin resistance. Thirty-two male Sprague-Dawley rats were assigned to four groups: control diet (Con)-sedentary (Sed); Con-RT; high-fat diet (HF)-Sed; and HF-RT. Animals consumed their respective diets for 9 wk; then RT animals performed 12 wk of training (3 sets, 10 repetitions at 75% one-repetition maximum, 3x/wk). Animals remained on their dietary treatments over the 12-wk period. After the training period, animals were subjected to hindlimb perfusions. Insulin-stimulated insulin receptor substrate-1-associated phosphatidylinositol-3 kinase activity was enhanced in the red gastrocnemius and quadriceps of Con-RT and HF-RT animals. Atypical PKC-zeta/lambda and Akt activities were reduced in HF-Sed and normalized in HF-RT animals. Resistance training increased GLUT-4 protein concentration in red gastrocnemius and quadriceps of Con-RT and HF-RT animals. No differences were observed in total protein concentrations of insulin receptor substrate-1, Akt, atypical PKC-zeta/lambda, or phosphorylation of Akt. Collectively, these findings suggest that resistance training increases insulin-stimulated carbohydrate metabolism in normal skeletal muscle and reverses high-fat diet-induced skeletal muscle insulin resistance by altering components of both the insulin signaling cascade and glucose transporter effector system.
authors.affiliation: Exercise Biochemistry Laboratory, Department of Kinesiology, College of Health and Human Development, California State University Northridge, Northridge, CA 91330-8287, USA.
authors.forename: Adam D
authors.initials: AD
authors.lastname: Krisan
authors.forename: Dale E
authors.initials: DE
authors.lastname: Collins
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Crain
authors.forename: Connie C
authors.initials: CC
authors.lastname: Kwong
authors.forename: Mohenish K
authors.initials: MK
authors.lastname: Singh
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Bernard
authors.forename: Ben B
authors.initials: BB
authors.lastname: Yaspelkis
mesh_terms: D019325:3-O-Methylglucose / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D004041:Dietary Fats / Q000008:administration & dosage* / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism; D051275:Glucose Transporter Type 4; D007328:Insulin / Q000378:metabolism*; D055504:Insulin Receptor Substrate Proteins; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology*; D009994:Osmolar Concentration; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011493:Protein Kinase C / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology*; D014891:Weight Lifting / Q000502:physiology*
chemical_list: D019325:3-O-Methylglucose; D004041:Dietary Fats; D005947:Glucose; D051275:Glucose Transporter Type 4; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D019869:Phosphatidylinositol 3-Kinases; D010750:Phosphoproteins; D011493:Protein Kinase C; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; C526296:Irs1 protein, rat; C495694:Slc2a4 protein, rat; C494920:Akt1 protein, rat; C115015:PKC-3 protein