AMPK activity and isoform protein expression are similar in muscle of obese subjects with and without type 2 diabetes

2004 ◽  
Vol 286 (2) ◽  
pp. E239-E244 ◽  
Author(s):  
Kurt Højlund ◽  
Kirsty J. Mustard ◽  
Peter Stæhr ◽  
D. Grahame Hardie ◽  
Henning Beck-Nielsen ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Protein Expression ◽  
Glycogen Synthesis ◽  
Control Subjects ◽  
Subunit Isoforms ◽  
Impaired Insulin Action ◽  
Amp Activated Protein Kinase ◽  
Type 2 Diabetic

Acute or chronic activation of AMP-activated protein kinase (AMPK) increases insulin sensitivity. Conversely, reduced expression and/or function of AMPK might play a role in insulin resistance in type 2 diabetes. Thus protein expression of the seven subunit isoforms of AMPK and activities and/or phosphorylation of AMPK and acetyl-CoA carboxylase-β (ACCβ) was measured in skeletal muscle from obese type 2 diabetic and well-matched control subjects during euglycemic-hyperinsulinemic clamps. Protein expression of all AMPK subunit isoforms (α1, α2, β1, β2, γ1, γ2, and γ3) in muscle of obese type 2 diabetic subjects was similar to that of control subjects. In addition, α1- and α2-associated activities of AMPK, phosphorylation of α-AMPK subunits at Thr172, and phosphorylation of ACCβ at Ser221 showed no difference between the two groups and were not regulated by physiological concentrations of insulin. These data suggest that impaired insulin action on glycogen synthesis and lipid oxidation in skeletal muscle of obese type 2 diabetic subjects is unlikely to involve changes in AMPK expression and activity.

scholarly journals Effects of raising muscle glycogen synthesis rate on skeletal muscle ATP turnover rate in type 2 diabetes

2011 ◽  
Vol 301 (6) ◽  
pp. E1155-E1162 ◽  
Author(s):  
Ee L. Lim ◽  
Kieren G. Hollingsworth ◽  
Fiona E. Smith ◽  
Peter E. Thelwall ◽  
Roy Taylor
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Muscle Glycogen ◽  
Glycogen Synthesis ◽  
Turnover Rates ◽  
Atp Turnover ◽  
Muscle Glycogen Synthesis ◽  
Type 2 Diabetic

Mitochondrial dysfunction has been implicated in the pathogenesis of type 2 diabetes. We hypothesized that any impairment in insulin-stimulated muscle ATP production could merely reflect the lower rates of muscle glucose uptake and glycogen synthesis, rather than cause it. If this is correct, muscle ATP turnover rates in type 2 diabetes could be increased if glycogen synthesis rates were normalized by the mass-action effect of hyperglycemia. Isoglycemic- and hyperglycemic-hyperinsulinemic clamps were performed on type 2 diabetic subjects and matched controls, with muscle ATP turnover and glycogen synthesis rates measured using 31P- and 13C-magnetic resonance spectroscopy, respectively. In diabetic subjects, hyperglycemia increased muscle glycogen synthesis rates to the level observed in controls at isoglycemia [from 19 ± 9 to 41 ± 12 μmol·l−1·min−1 ( P = 0.012) vs. 40 ± 7 μmol·l−1·min−1 in controls]. This was accompanied by a modest increase in muscle ATP turnover rates (7.1 ± 0.5 vs. 8.6 ± 0.7 μmol·l−1·min−1, P = 0.04). In controls, hyperglycemia brought about a 2.5-fold increase in glycogen synthesis rates (100 ± 24 vs. 40 ± 7 μmol·l−1·min−1, P = 0.028) and a 23% increase in ATP turnover rates (8.1 ± 0.9 vs. 10.0 ± 0.9 μmol·l−1·min−1, P = 0.025) from basal state. Muscle ATP turnover rates correlated positively with glycogen synthesis rates ( rs = 0.46, P = 0.005). Changing the rate of muscle glucose metabolism in type 2 diabetic subjects alters demand for ATP synthesis at rest. In type 2 diabetes, skeletal muscle ATP turnover rates reflect the rate of glucose uptake and glycogen synthesis, rather than any primary mitochondrial defect.

scholarly journals Low-Dose Acrolein, an Endogenous and Exogenous Toxic Molecule, Inhibits Glucose Transport via an Inhibition of Akt-Regulated GLUT4 Signaling in Skeletal Muscle Cells

2021 ◽  
Vol 22 (13) ◽  
pp. 7228
Author(s):  
Ching-Chia Wang ◽  
Huang-Jen Chen ◽  
Ding-Cheng Chan ◽  
Chen-Yuan Chiu ◽  
Shing-Hwa Liu ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glucose Metabolism ◽  
Glucose Tolerance ◽  
Protein Expression ◽  
Glucose Uptake ◽  
Glucose Transport ◽  
Diabetic Patients ◽  
Type 2 Diabetic Patients ◽  
Type 2 Diabetic

Urinary acrolein adduct levels have been reported to be increased in both habitual smokers and type-2 diabetic patients. The impairment of glucose transport in skeletal muscles is a major factor responsible for glucose uptake reduction in type-2 diabetic patients. The effect of acrolein on glucose metabolism in skeletal muscle remains unclear. Here, we investigated whether acrolein affects muscular glucose metabolism in vitro and glucose tolerance in vivo. Exposure of mice to acrolein (2.5 and 5 mg/kg/day) for 4 weeks substantially increased fasting blood glucose and impaired glucose tolerance. The glucose transporter-4 (GLUT4) protein expression was significantly decreased in soleus muscles of acrolein-treated mice. The glucose uptake was significantly decreased in differentiated C2C12 myotubes treated with a non-cytotoxic dose of acrolein (1 μM) for 24 and 72 h. Acrolein (0.5–2 μM) also significantly decreased the GLUT4 expression in myotubes. Acrolein suppressed the phosphorylation of glucose metabolic signals IRS1, Akt, mTOR, p70S6K, and GSK3α/β. Over-expression of constitutive activation of Akt reversed the inhibitory effects of acrolein on GLUT4 protein expression and glucose uptake in myotubes. These results suggest that acrolein at doses relevant to human exposure dysregulates glucose metabolism in skeletal muscle cells and impairs glucose tolerance in mice.

scholarly journals Dysfunction of muscle contraction with impaired intracellular Ca2+ handling in skeletal muscle and the effect of exercise training in male db/db mice

2019 ◽  
Vol 126 (1) ◽  
pp. 170-182 ◽  
Author(s):  
Hiroaki Eshima ◽  
Yoshifumi Tamura ◽  
Saori Kakehi ◽  
Kyoko Nakamura ◽  
Nagomi Kurebayashi ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Exercise Training ◽  
Muscle Contraction ◽  
Contractile Function ◽  
Contractile Force ◽  
Contractile Dysfunction ◽  
Muscle Contractile ◽  
Type 2 Diabetic

Type 2 diabetes is characterized by reduced contractile force production and increased fatigability of skeletal muscle. While the maintenance of Ca2+ homeostasis during muscle contraction is a requisite for optimal contractile function, the mechanisms underlying muscle contractile dysfunction in type 2 diabetes are unclear. Here, we investigated skeletal muscle contractile force and Ca2+ flux during contraction and pharmacological stimulation in type 2 diabetic model mice ( db/db mice). Furthermore, we investigated the effect of treadmill exercise training on muscle contractile function. In male db/db mice, muscle contractile force and peak Ca2+ levels were both lower during tetanic stimulation of the fast-twitch muscles, while Ca2+ accumulation was higher after stimulation compared with control mice. While 6 wk of exercise training did not improve glucose tolerance, exercise did improve muscle contractile dysfunction, peak Ca2+ levels, and Ca2+ accumulation following stimulation in male db/db mice. These data suggest that dysfunctional Ca2+ flux may contribute to skeletal muscle contractile dysfunction in type 2 diabetes and that exercise training may be a promising therapeutic approach for dysfunctional skeletal muscle contraction. NEW & NOTEWORTHY The purpose of this study was to examine muscle contractile function and Ca2+ regulation as well as the effect of exercise training in skeletal muscle in obese diabetic mice ( db/db). We observed impairment of muscle contractile force and Ca2+ regulation in a male type 2 diabetic animal model. These dysfunctions in muscle were improved by 6 wk of exercise training.

scholarly journals Intermuscular Fat Content in Young Chinese Men With Newly Diagnosed Type 2 Diabetes: Based on MR mDIXON-Quant Quantitative Technique

2021 ◽  
Vol 12 ◽  
Author(s):  
Fuyao Yu ◽  
Bing He ◽  
Li Chen ◽  
Fengzhe Wang ◽  
Haidong Zhu ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Fat Content ◽  
Control Group ◽  
Diabetic Patients ◽  
Diabetes Group ◽  
Control Subjects ◽  
Intermuscular Fat ◽  
And Control

ObjectiveSkeletal muscle fat content is one of the important contributors to insulin resistance (IR), but its diagnostic value remains unknown, especially in the Chinese population. Therefore, we aimed to analyze differences in skeletal muscle fat content and various functional MRI parameters between diabetic patients and control subjects to evaluate the early indicators of diabetes. In addition, we aimed to investigate the associations among skeletal muscle fat content, magnetic resonance parameters of skeletal muscle function and IR in type 2 diabetic patients and control subjects.MethodsWe enrolled 12 patients (age:29-38 years, BMI: 25-28 kg/m2) who were newly diagnosed with type 2 diabetes (intravenous plasma glucose concentration≥11.1mmol/l or fasting blood glucose concentration≥7.0mmol/l) together with 12 control subjects as the control group (age: 26-33 years, BMI: 21-28 kg/m2). Fasting blood samples were collected for the measurement of glucose, insulin, 2-hour postprandial blood glucose (PBG2h), and glycated hemoglobin (HbAlc). The magnetic resonance scan of the lower extremity and abdomen was performed, which can evaluate visceral fat content as well as skeletal muscle metabolism and function through transverse relaxation times (T2), fraction anisotropy (FA) and apparent diffusion coefficient (ADC) values.ResultsWe found a significant difference in intermuscular fat (IMAT) between the diabetes group and the control group (p<0.05), the ratio of IMAT in thigh muscles of diabetes group was higher than that of control group. In the entire cohort, IMAT was positively correlated with HOMA-IR, HbAlc, T2, and FA, and the T2 value was correlated with HOMA-IR, PBG2h and HbAlc (p<0.05). There were also significant differences in T2 and FA values between the diabetes group and the control group (p<0.05). According to the ROC, assuming 8.85% of IMAT as the cutoff value, the sensitivity and specificity of IMAT were 100% and 83.3%, respectively. Assuming 39.25ms as the cutoff value, the sensitivity and specificity of T2 value were 66.7% and 91.7%, respectively. All the statistical analyses were adjusted for age, BMI and visceral fat content.ConclusionDeposition of IMAT in skeletal muscles seems to be an important determinant for IR in type 2 diabetes. The skeletal muscle IMAT value greater than 8.85% and the T2 value greater than 39.25ms are suggestive of IR.

scholarly journals Metformin Increases AMP-Activated Protein Kinase Activity in Skeletal Muscle of Subjects With Type 2 Diabetes

Diabetes ◽  
2002 ◽  
Vol 51 (7) ◽  
pp. 2074-2081 ◽  
Author(s):  
N. Musi ◽  
M. F. Hirshman ◽  
J. Nygren ◽  
M. Svanfeldt ◽  
P. Bavenholm ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Protein Kinase ◽  
Kinase Activity ◽  
Protein Kinase Activity ◽  
Amp Activated Protein Kinase

scholarly journals Plasma FFA utilization and fatty acid-binding protein content are diminished in type 2 diabetic muscle

2000 ◽  
Vol 279 (1) ◽  
pp. E146-E154 ◽  
Author(s):  
Ellen E. Blaak ◽  
Anton J. M. Wagenmakers ◽  
Jan F. C. Glatz ◽  
Bruce H. R. Wolffenbuttel ◽  
Gerrit J. Kemerink ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Fatty Acid ◽  
Fatty Acid Binding Protein ◽  
Fatty Acid Binding ◽  
Acid Binding Protein ◽  
Fasted State ◽  
Plasma Ffa ◽  
Type 2 Diabetic

In this study, we investigated the hypothesis that impairments in forearm skeletal muscle free fatty acid (FFA) metabolism are present in patients with type 2 diabetes both in the overnight fasted state and during β-adrenergic stimulation. Eight obese subjects with type 2 diabetes and eight nonobese controls (Con) were studied using the forearm balance technique and indirect calorimetry during infusion of the stable isotope tracer [U-13C]palmitate after an overnight fast and during infusion of the nonselective β-agonist isoprenaline (Iso, 20 ng · kg lean body mass−1 · min−1). Additionally, activities of mitochondrial enzymes and of cytoplasmatic fatty acid-binding protein (FABP) were determined in biopsies from the vastus lateralis muscle. Both during fasting and Iso infusion, the tracer balance data showed that forearm muscle FFA uptake (Con vs. type 2: fast 449 ± 69 vs. 258 ± 42 and Iso 715 ± 129 vs. 398 ± 70 nmol · 100 ml tissue−1 · min−1, P < 0.05) and FFA release were lower in type 2 diabetes compared with Con. Also, the oxidation of plasma FFA by skeletal muscle was blunted during Iso infusion in type 2 diabetes (Con vs. type 2: Iso 446 ± 274 vs. 16 ± 70 nmol · 100 ml tissue−1 · min−1, P < 0.05). The net forearm glycerol release was increased in type 2 diabetic subjects ( P < 0.05), which points to an increased forearm lipolysis. Additionally, skeletal muscle cytoplasmatic FABP content and the activity of muscle oxidative enzymes were lowered in type 2 diabetes. We conclude that the uptake and oxidation of plasma FFA are impaired in the forearm muscles of type 2 diabetic subjects in the overnight fasted state with and without Iso stimulation.

scholarly journals Gymnemic acid, a potent antidiabetic agent protects skeletal muscle from hyperglycemia mediated oxidative stress and apoptotic events in High fat and High fructose diet fed adult rats

2020 ◽  
Vol 11 (2) ◽  
pp. 1526-1538
Author(s):  
Porkodi Karthikeyan ◽  
Lakshmi Narasimhan Chakrapani ◽  
Thangarajeswari Mohan ◽  
Bhavani Tamilarasan ◽  
Pughazhendi Kannan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Diabetic Rats ◽  
High Fat ◽  
Gymnemic Acid ◽  
High Fructose ◽  
Type 2 Diabetic

Type 2 diabetes is delineated by impaired metabolic flexibility, and intramyocellular lipid accumulation, causing insulin resistance, particularly in skeletal muscle by reducing insulin-stimulated glucose uptake. High-fat diet and high fructose (HFD and HF) administration in rodents bestows a model for hyperlipidemia, insulin resistance, and Type 2 diabetes. The current study is focused on elucidating the role of Gymnemic acid in combating hyperglycemia mediated oxidative stress and apoptotic events in the skeletal muscle of HFD and HF induced Type 2 diabetes in Wistar albino rats by boosting antioxidant defense system. Gymnemic acid, a saponin of triterpene glycoside contained in leaves of Gymnema Sylvestre, has potent anti-diabetic properties. Treatment with Gymnemic acid restored the antioxidant status (Gpx, SOD, CAT, GR, Vit C & Vit E) with significant (p<0.05) decrease in free radical levels and reinvigorated the expression of apoptotic and antiapoptotic proteins in Type 2 diabetic rats. Histopathological data demonstrate that oral administration of Gymnemic acid protects skeletal muscle fibers from an oxidative niche in HFD and HF in Type 2 diabetic rats. In accordance with this, Gymnemic acid might be regarded as a promising therapeutic agent against Type 2 diabetes, thereby restoring skeletal muscle integrity and function.

Sign in / Sign up

Export Citation Format

Share Document