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Takahashi K, Kitaoka YU, Matsunaga Y, Hatta H. Effects of Endurance Training on Metabolic Enzyme Activity and Transporter Proteins in Skeletal Muscle of Ovariectomized Mice. Med Sci Sports Exerc 2023; 55:186-198. [PMID: 36170569 DOI: 10.1249/mss.0000000000003045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
PURPOSE Estrogen deficiency or insufficiency can occur under several conditions, leading to negative health outcomes. To establish an effective countermeasure against estrogen loss, we investigated the effects of endurance training on ovariectomy (OVX)-induced metabolic disturbances. METHODS Female Institute of Cancer Research mice underwent OVX or sham operations. On day 7 of recovery, the mice were randomized to remain either sedentary or undergo 5 wk of treadmill running (15-20 m·min -1 , 60 min, 5 d·wk -1 ). During week 5 of the training, all animals performed a treadmill running test (15 m·min -1 , 60 min). RESULTS After the experimental period, OVX resulted in greater gains in body mass, fat mass, and triglyceride content in the gastrocnemius muscle. OVX enhanced phosphofructokinase activity in the plantaris muscle and decreased lactate dehydrogenase activity in the plantaris and soleus muscles. OVX decreased the protein content of NDUFB8, a mitochondrial respiratory chain subunit, but did not decrease other mitochondrial proteins or enzyme activities. Endurance training significantly enhanced mitochondrial enzyme activity and protein content in the skeletal muscles. Although OVX increased the respiratory exchange ratio during the treadmill running test, and postexercise blood lactate levels, endurance training normalized these parameters. CONCLUSIONS The present findings suggest that endurance training is a viable strategy to counteract the negative metabolic consequences in hypoestrogenism.
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Affiliation(s)
- Kenya Takahashi
- Department of Sports Sciences, The University of Tokyo, Tokyo, JAPAN
| | - Y U Kitaoka
- Department of Human Sciences, Kanagawa University, Kanagawa, JAPAN
| | - Yutaka Matsunaga
- Department of Sports Sciences, The University of Tokyo, Tokyo, JAPAN
| | - Hideo Hatta
- Department of Sports Sciences, The University of Tokyo, Tokyo, JAPAN
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Factors Influencing Substrate Oxidation During Submaximal Cycling: A Modelling Analysis. Sports Med 2022; 52:2775-2795. [PMID: 35829994 PMCID: PMC9585001 DOI: 10.1007/s40279-022-01727-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2022] [Indexed: 02/01/2023]
Abstract
BACKGROUND Multiple factors influence substrate oxidation during exercise including exercise duration and intensity, sex, and dietary intake before and during exercise. However, the relative influence and interaction between these factors is unclear. OBJECTIVES Our aim was to investigate factors influencing the respiratory exchange ratio (RER) during continuous exercise and formulate multivariable regression models to determine which factors best explain RER during exercise, as well as their relative influence. METHODS Data were extracted from 434 studies reporting RER during continuous cycling exercise. General linear mixed-effect models were used to determine relationships between RER and factors purported to influence RER (e.g., exercise duration and intensity, muscle glycogen, dietary intake, age, and sex), and to examine which factors influenced RER, with standardized coefficients used to assess their relative influence. RESULTS The RER decreases with exercise duration, dietary fat intake, age, VO2max, and percentage of type I muscle fibers, and increases with dietary carbohydrate intake, exercise intensity, male sex, and carbohydrate intake before and during exercise. The modelling could explain up to 59% of the variation in RER, and a model using exclusively easily modified factors (exercise duration and intensity, and dietary intake before and during exercise) could only explain 36% of the variation in RER. Variables with the largest effect on RER were sex, dietary intake, and exercise duration. Among the diet-related factors, daily fat and carbohydrate intake have a larger influence than carbohydrate ingestion during exercise. CONCLUSION Variability in RER during exercise cannot be fully accounted for by models incorporating a range of participant, diet, exercise, and physiological characteristics. To better understand what influences substrate oxidation during exercise further research is required on older subjects and females, and on other factors that could explain additional variability in RER.
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Rothschild JA, Islam H, Bishop DJ, Kilding AE, Stewart T, Plews DJ. Factors Influencing AMPK Activation During Cycling Exercise: A Pooled Analysis and Meta-Regression. Sports Med 2021; 52:1273-1294. [PMID: 34878641 DOI: 10.1007/s40279-021-01610-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2021] [Indexed: 01/14/2023]
Abstract
BACKGROUND The 5' adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a cellular energy sensor that is activated by increases in the cellular AMP/adenosine diphosphate:adenosine triphosphate (ADP:ATP) ratios and plays a key role in metabolic adaptations to endurance training. The degree of AMPK activation during exercise can be influenced by many factors that impact on cellular energetics, including exercise intensity, exercise duration, muscle glycogen, fitness level, and nutrient availability. However, the relative importance of these factors for inducing AMPK activation remains unclear, and robust relationships between exercise-related variables and indices of AMPK activation have not been established. OBJECTIVES The purpose of this analysis was to (1) investigate correlations between factors influencing AMPK activation and the magnitude of change in AMPK activity during cycling exercise, (2) investigate correlations between commonly reported measures of AMPK activation (AMPK-α2 activity, phosphorylated (p)-AMPK, and p-acetyl coenzyme A carboxylase (p-ACC), and (3) formulate linear regression models to determine the most important factors for AMPK activation during exercise. METHODS Data were pooled from 89 studies, including 982 participants (93.8% male, maximal oxygen consumption [[Formula: see text]] 51.9 ± 7.8 mL kg-1 min-1). Pearson's correlation analysis was performed to determine relationships between effect sizes for each of the primary outcome markers (AMPK-α2 activity, p-AMPK, p-ACC) and factors purported to influence AMPK signaling (muscle glycogen, carbohydrate ingestion, exercise duration and intensity, fitness level, and muscle metabolites). General linear mixed-effect models were used to examine which factors influenced AMPK activation. RESULTS Significant correlations (r = 0.19-0.55, p < .05) with AMPK activity were found between end-exercise muscle glycogen, exercise intensity, and muscle metabolites phosphocreatine, creatine, and free ADP. All markers of AMPK activation were significantly correlated, with the strongest relationship between AMPK-α2 activity and p-AMPK (r = 0.56, p < 0.001). The most important predictors of AMPK activation were the muscle metabolites and exercise intensity. CONCLUSION Muscle glycogen, fitness level, exercise intensity, and exercise duration each influence AMPK activity during exercise when all other factors are held constant. However, disrupting cellular energy charge is the most influential factor for AMPK activation during endurance exercise.
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Affiliation(s)
- Jeffrey A Rothschild
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand.
| | - Hashim Islam
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - David J Bishop
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, VIC, Australia.,School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
| | - Andrew E Kilding
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Tom Stewart
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Daniel J Plews
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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Gudiksen A, Qoqaj A, Ringholm S, Wojtaszewski J, Plomgaard P, Pilegaard H. Ameliorating effects of lifelong physical activity on healthy aging and mitochondrial function in human white adipose tissue. J Gerontol A Biol Sci Med Sci 2021; 77:1101-1111. [PMID: 34875059 DOI: 10.1093/gerona/glab356] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Indexed: 11/12/2022] Open
Abstract
Growing old is patently among the most prominent risk factors for lifestyle related diseases and deterioration in physical performance. Aging in particular affects mitochondrial homeostasis and maintaining a well-functioning mitochondrial pool is imperative in order to avoid age-associated metabolic decline. White adipose tissue (WAT) is a key organ in energy balance and impaired mitochondrial function in adipocytes has been associated with increased low-grade inflammation, altered metabolism, excessive ROS production and an accelerated aging phenotype. Exercise training improves mitochondrial health but whether lifelong exercise training can sufficiently maintain WAT mitochondrial function is currently unknown. Therefore, to dissect the role and dose-dependence of lifelong exercise training on aging WAT metabolic parameters and mitochondrial function, young and older untrained, as well as moderately and highly exercise trained older male subjects were recruited and abdominal subcutaneous (s)WAT biopsies and venous blood samples were obtained to measure mitochondrial function and key metabolic factors in WAT and plasma. Mitochondrial intrinsic respiratory capacity was lower in sWAT from older than in young subjects. In spite of this, maximal mitochondrial respiration per wet weight, markers of oxidative capacity, and mitophagic capacity were increased in sWAT from lifelong highly exercise trained than all other groups. Furthermore, ROS emission was generally lower in sWAT from lifelong highly exercise trained than older untrained subjects. Taken together, aging reduces intrinsic mitochondrial respiration in human sWAT, but lifelong high volume exercise training increases oxidative capacity by increasing mitochondrial volume likely contributing to healthy aging.
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Affiliation(s)
- Anders Gudiksen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Albina Qoqaj
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Stine Ringholm
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen Wojtaszewski
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Peter Plomgaard
- Department of Clinical Biochemistry, Centre of Inflammation and Metabolism, and Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Henriette Pilegaard
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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Suppression of Pyruvate Dehydrogenase Kinase by Dichloroacetate in Cancer and Skeletal Muscle Cells Is Isoform Specific and Partially Independent of HIF-1α. Int J Mol Sci 2021; 22:ijms22168610. [PMID: 34445316 PMCID: PMC8395311 DOI: 10.3390/ijms22168610] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/28/2021] [Accepted: 08/03/2021] [Indexed: 02/01/2023] Open
Abstract
Inhibition of pyruvate dehydrogenase kinase (PDK) emerged as a potential strategy for treatment of cancer and metabolic disorders. Dichloroacetate (DCA), a prototypical PDK inhibitor, reduces the abundance of some PDK isoenzymes. However, the underlying mechanisms are not fully characterized and may differ across cell types. We determined that DCA reduced the abundance of PDK1 in breast (MDA-MB-231) and prostate (PC-3) cancer cells, while it suppressed both PDK1 and PDK2 in skeletal muscle cells (L6 myotubes). The DCA-induced PDK1 suppression was partially dependent on hypoxia-inducible factor-1α (HIF-1α), a transcriptional regulator of PDK1, in cancer cells but not in L6 myotubes. However, the DCA-induced alterations in the mRNA and the protein levels of PDK1 and/or PDK2 did not always occur in parallel, implicating a role for post-transcriptional mechanisms. DCA did not inhibit the mTOR signaling, while inhibitors of the proteasome or gene silencing of mitochondrial proteases CLPP and AFG3L2 did not prevent the DCA-induced reduction of the PDK1 protein levels. Collectively, our results suggest that DCA reduces the abundance of PDK in an isoform-dependent manner via transcriptional and post-transcriptional mechanisms. Differential response of PDK isoenzymes to DCA might be important for its pharmacological effects in different types of cells.
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Bruhn L, Kjøbsted R, Quist JS, Gram AS, Rosenkilde M, Færch K, Wojtaszewski JF, Stallknecht B, Blond MB. Effect of exercise training on skeletal muscle protein expression in relation to insulin sensitivity: Per-protocol analysis of a randomized controlled trial (GO-ACTIWE). Physiol Rep 2021; 9:e14850. [PMID: 34042297 PMCID: PMC8157763 DOI: 10.14814/phy2.14850] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 04/08/2021] [Indexed: 12/14/2022] Open
Abstract
Exercise training improves peripheral insulin sensitivity and leads to molecular adaptations in the skeletal muscle. We investigated changes in the expression of key muscle proteins in the glucose metabolic pathway following active commuting by bike or leisure-time exercise at two different intensities. In addition, potential associations between insulin sensitivity and muscle protein expression were examined. This per-protocol analysis included 72 out of 130 physically inactive, healthy women and men (20-45 years) with overweight/obesity (BMI: 25-35 kg/m2 ) who completed 6 months of no intervention (CON, n = 12), active commuting by bike (BIKE, n = 14), or leisure-time exercise of moderate (MOD, n = 28) or vigorous (VIG, n = 18) intensity. Exercise was prescribed 5 days/week with a weekly exercise energy expenditure of 1,600 kcal for women and 2,100 kcal for men. Insulin sensitivity was determined by a hyperinsulinemic euglycemic clamp and skeletal muscle biopsies were obtained from m. vastus lateralis and analyzed for protein expression at baseline and after 3 and 6 months of intervention. We found an increased expression of pyruvate dehydrogenase (PDH) in the exercise groups compared with the control group following 6 months of training. No differential effects were observed on the protein expression following moderate versus vigorous intensity exercise. In addition, we found a positive association between insulin sensitivity and the expression of glucose transporter type 4 as well as PDH. The positive association and the increase in expression of PDH after exercise training points toward a role for PDH in the training-induced enhancement of insulin sensitivity.
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Affiliation(s)
- Lea Bruhn
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Steno Diabetes Center CopenhagenGentofteDenmark
| | - Rasmus Kjøbsted
- Section of Molecular PhysiologyAugust Krogh ClubDepartment of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
| | - Jonas Salling Quist
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Steno Diabetes Center CopenhagenGentofteDenmark
| | - Anne Sofie Gram
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Mads Rosenkilde
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Kristine Færch
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Steno Diabetes Center CopenhagenGentofteDenmark
| | - Jørgen F.P. Wojtaszewski
- Section of Molecular PhysiologyAugust Krogh ClubDepartment of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
| | - Bente Stallknecht
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Martin Bæk Blond
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Steno Diabetes Center CopenhagenGentofteDenmark
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Zhao T, Le S, Freitag N, Schumann M, Wang X, Cheng S. Effect of Chronic Exercise Training on Blood Lactate Metabolism Among Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis. Front Physiol 2021; 12:652023. [PMID: 33776804 PMCID: PMC7992008 DOI: 10.3389/fphys.2021.652023] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/17/2021] [Indexed: 12/29/2022] Open
Abstract
Purpose: To assess the effect of chronic exercise training on blood lactate metabolism at rest (i.e., basal lactate concentrations) and during exercise (i.e., blood lactate concentration at a fixed load, load at a fixed blood lactate concentration, and load at the individual blood lactate threshold) among patients with type 2 diabetes mellitus (T2DM). Methods: PubMed (MedLine), Embase, Web of Science, and Scopus were searched. Randomized controlled trials, non-randomized controlled trials, and case-control studies using chronic exercise training (i.e., 4 weeks) and that assessed blood lactate concentrations at rest and during exercise in T2DM patients were included. Results: Thirteen studies were eligible for the systematic review, while 12 studies with 312 participants were included into the meta-analysis. In the pre-to-post intervention meta-analysis, chronic exercise training had no significant effect on changes in basal blood lactate concentrations (standardized mean difference (SMD) = -0.20; 95% CI, -0.55 to 0.16; p = 0.28), and the results were similar when comparing the effect of intervention and control groups. Furthermore, blood lactate concentration at a fixed load significantly decreased (SMD = -0.73; 95% CI, -1.17 to -0.29; p = 0.001), while load at a fixed blood lactate concentration increased (SMD = 0.40; 95% CI, 0.07 to 0.72; p = 0.02) after chronic exercise training. No change was observed in load at the individual blood lactate threshold (SMD = 0.28; 95% CI, -0.14 to 0.71; p = 0.20). Conclusion: Chronic exercise training does not statistically affect basal blood lactate concentrations; however, it may decrease the blood lactate concentrations during exercise, indicating improvements of physical performance capacity which is beneficial for T2DM patients' health in general. Why chronic exercise training did not affect basal blood lactate concentrations needs further investigation.
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Affiliation(s)
- Tong Zhao
- Exercise, Health and Technology Centre, Department of Physical Education, Shanghai Jiao Tong University, Shanghai, China
| | - Shenglong Le
- Exercise, Health and Technology Centre, Department of Physical Education, Shanghai Jiao Tong University, Shanghai, China.,Faculty of Sport and Health Science, University of Jyväskylä, Jyväskylä, Finland.,Exercise Translational Medicine Centre, Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China.,School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Nils Freitag
- Department of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University, Cologne, Germany.,Olympic Training Center Berlin, Berlin, Germany
| | - Moritz Schumann
- Exercise Translational Medicine Centre, Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China.,Department of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University, Cologne, Germany
| | - Xiuqiang Wang
- Exercise, Health and Technology Centre, Department of Physical Education, Shanghai Jiao Tong University, Shanghai, China.,Exercise Translational Medicine Centre, Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Sulin Cheng
- Exercise, Health and Technology Centre, Department of Physical Education, Shanghai Jiao Tong University, Shanghai, China.,Faculty of Sport and Health Science, University of Jyväskylä, Jyväskylä, Finland.,Exercise Translational Medicine Centre, Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China.,School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.,Department of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University, Cologne, Germany
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Hjelholt AJ, Charidemou E, Griffin JL, Pedersen SB, Gudiksen A, Pilegaard H, Jessen N, Møller N, Jørgensen JOL. Insulin resistance induced by growth hormone is linked to lipolysis and associated with suppressed pyruvate dehydrogenase activity in skeletal muscle: a 2 × 2 factorial, randomised, crossover study in human individuals. Diabetologia 2020; 63:2641-2653. [PMID: 32945898 DOI: 10.1007/s00125-020-05262-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 07/15/2020] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Growth hormone (GH) causes insulin resistance that is linked to lipolysis, but the underlying mechanisms are unclear. We investigated if GH-induced insulin resistance in skeletal muscle involves accumulation of diacylglycerol (DAG) and ceramide as well as impaired insulin signalling, or substrate competition between fatty acids and glucose. METHODS Nine GH-deficient male participants were randomised and examined in a 2 × 2 factorial design with and without administration of GH and acipimox (an anti-lipolytic compound). As-treated analyses were performed, wherefore data from three visits from two patients were excluded due to incorrect GH administration. The primary outcome was insulin sensitivity, expressed as the AUC of the glucose infusion rate (GIRAUC), and furthermore, the levels of DAGs and ceramides, insulin signalling and the activity of the active form of pyruvate dehydrogenase (PDHa) were assessed in skeletal muscle biopsies obtained in the basal state and during a hyperinsulinaemic-euglycaemic clamp (HEC). RESULTS Co-administration of acipimox completely suppressed the GH-induced elevation in serum levels of NEFA (GH versus GH+acipimox, p < 0.0001) and abrogated GH-induced insulin resistance (mean GIRAUC [95% CI] [mg min-1 kg-1] during the HEC: control, 595 [493, 718]; GH, 468 [382, 573]; GH+acipimox, 654 [539, 794]; acipimox, 754 [618, 921]; GH vs GH+acipimox: p = 0.004). GH did not significantly change either the accumulation of DAGs and ceramides or insulin signalling in skeletal muscle, but GH antagonised the insulin-stimulated increase in PDHa activity (mean ± SEM [% from the basal state to the HEC]: control, 47 ± 19; GH, -15 ± 21; GH+acipimox, 3 ± 21; acipimox, 57 ± 22; main effect: p = 0.02). CONCLUSIONS/INTERPRETATION GH-induced insulin resistance in skeletal muscle is: (1) causally linked to lipolysis; (2) not associated with either accumulation of DAGs and ceramides or impaired insulin signalling; (3) likely to involve substrate competition between glucose and lipid intermediates. TRIAL REGISTRATION ClinicalTrials.gov NCT02782208 FUNDING: The work was supported by the Grant for Growth Innovation (GGI), which was funded by Merck KGaA, Darmstadt, Germany. Graphical abstract.
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Affiliation(s)
- Astrid J Hjelholt
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus N, Denmark.
- Department of Clinical Pharmacology, Aarhus University Hospital, Aarhus C, Denmark.
| | - Evelina Charidemou
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK
| | - Julian L Griffin
- Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK
| | - Steen B Pedersen
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus N, Denmark
| | - Anders Gudiksen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Henriette Pilegaard
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Niels Jessen
- Department of Clinical Pharmacology, Aarhus University Hospital, Aarhus C, Denmark
- Steno Diabetes Centre Aarhus, Aarhus University Hospital, Aarhus N, Denmark
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Niels Møller
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus N, Denmark
| | - Jens O L Jørgensen
- Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus N, Denmark
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Wang X, Lai S, Ye Y, Hu Y, Pan D, Bai X, Shen J. Conditional knockout of pyruvate dehydrogenase in mouse pancreatic β‑cells causes morphological and functional changes. Mol Med Rep 2020; 21:1717-1726. [PMID: 32319629 PMCID: PMC7057776 DOI: 10.3892/mmr.2020.10993] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 08/12/2019] [Indexed: 12/14/2022] Open
Abstract
Diabetes mellitus is a metabolic disorder predominantly caused by the dysfunction of pancreatic β-cells. This dysfunction is partly caused by the dysregulation of pyruvate dehydrogenase (PDH), which acts as an important mediator of pyruvate oxidation after glycolysis and fuels the tricarboxylic acid cycle. Previous studies have reported decreased PDH expression in rodent models and humans with type 2 diabetes mellitus (T2DM), suggesting that PDH may play an important role in the development of T2DM. However, the mechanism by which PDH affects insulin secretion and β-cell development is poorly understood. Using immunofluorescence staining, the present study found that the expression of pyruvate dehydrogenase E1-α subunit (PDHA1; encoded by the PDHA1 gene) in the islets of type 2 diabetic mice (db/db mice) was lower than in wild-type mice, which indicated the possible association between PDHA1and diabetes. To further understand this mechanism, an inducible, islet-specific PDHA1 knockout mouse (βKO) model was established. The phenotype was authenticated, and the blood glucose levels and islet function between the βKO and control mice were compared. Though no changes were found in food intake, development status, fasting blood glucose or weight between the groups, the level of insulin secretion at 30 min after glucose injection in the βKO group was significantly lower compared with the control group. Furthermore, the performed of the βKO mice on the intraperitoneal glucose tolerance test was visibly impaired when compared with the control mice. Pancreatic tissues were collected for hematoxylin and eosin staining, immunohistochemical and confocal laser-scanning microscopy analysis. Examination of the islets from the βKO mouse model indicated that abolishing the expression of PDH caused a compensatory islet enlargement and impaired insulin secretion.
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Affiliation(s)
- Xiao Wang
- Shunde Hospital of Southern Medical University, Foshan, Guangdong 528308, P.R. China
| | - Shuchang Lai
- The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan 570100, P.R. China
| | - Yanshi Ye
- Department of Endocrinology, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong 510000, P.R. China
| | - Yuanyuan Hu
- Shenzhen Nan Shan Hospital, Shenzhen, Guangdong 518052, P.R. China
| | - Daoyan Pan
- Department of Endocrinology, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong 510000, P.R. China
| | - Xiaochun Bai
- Department of Endocrinology, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong 510000, P.R. China
| | - Jie Shen
- Department of Endocrinology, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong 510000, P.R. China
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11
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Gudiksen A, Bertholdt L, Stankiewicz T, Villesen I, Bangsbo J, Plomgaard P, Pilegaard H. Training state and fasting-induced PDH regulation in human skeletal muscle. Pflugers Arch 2018; 470:1633-1645. [DOI: 10.1007/s00424-018-2164-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/17/2018] [Accepted: 06/07/2018] [Indexed: 12/13/2022]
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