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Rugg C, Schmid S, Zipperle J, Kreutziger J. Stress hyperglycaemia following trauma - a survival benefit or an outcome detriment? Curr Opin Anaesthesiol 2024; 37:131-138. [PMID: 38390910 DOI: 10.1097/aco.0000000000001350] [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: 02/24/2024]
Abstract
PURPOSE OF REVIEW Stress hyperglycaemia occur often in critically injured patients. To gain new consideration about it, this review compile current as well as known immunological and biochemical findings about causes and emergence. RECENT FINDINGS Glucose is the preferred energy substrate for fending immune cells, reparative tissue and the cardiovascular system following trauma. To fulfil these energy needs, the liver is metabolically reprogrammed to rebuild glucose from lactate and glucogenic amino acids (hepatic insulin resistance) at the expenses of muscles mass and - to a less extent - fat tissue (proteolysis, lipolysis, peripheral insulin resistance). This inevitably leads to stress hyperglycaemia, which is evolutionary preserved and seems to be an essential and beneficial survival response. It is initiated by damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs), intensified by immune cells itself and mainly ruled by tumour necrosis factor (TNF)α and catecholamines with lactate and hypoxia inducible factor (HIF)-1α as intracellular signals and lactate as an energy shuttle. Important biochemical mechanisms involved in this response are the Warburg effect as an efficient metabolic shortcut and the extended Cori cycle. SUMMARY Stress hyperglycaemia is beneficial in an acute life-threatening situation, but further research is necessary, to prevent trauma patients from the detrimental effects of persisting hyperglycaemia.
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Affiliation(s)
- Christopher Rugg
- Department of Anaesthesia and Intensive Care Medicine, Medical University of Innsbruck, Innsbruck, Austria
| | - Stefan Schmid
- Department of Anaesthesia and Intensive Care Medicine, Medical University of Innsbruck, Innsbruck, Austria
| | - Johannes Zipperle
- Johannes Zipperle, Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, Vienna, Austria
| | - Janett Kreutziger
- Department of Anaesthesia and Intensive Care Medicine, Medical University of Innsbruck, Innsbruck, Austria
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Gupta R, Wang M, Ma Y, Offermanns S, Whim MD. The β-Hydroxybutyrate-GPR109A Receptor Regulates Fasting-induced Plasticity in the Mouse Adrenal Medulla. Endocrinology 2022; 163:6590010. [PMID: 35595517 PMCID: PMC9188660 DOI: 10.1210/endocr/bqac077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Indexed: 11/19/2022]
Abstract
During fasting, increased sympathoadrenal activity leads to epinephrine release and multiple forms of plasticity within the adrenal medulla including an increase in the strength of the preganglionic → chromaffin cell synapse and elevated levels of agouti-related peptide (AgRP), a peptidergic cotransmitter in chromaffin cells. Although these changes contribute to the sympathetic response, how fasting evokes this plasticity is not known. Here we report these effects involve activation of GPR109A (HCAR2). The endogenous agonist of this G protein-coupled receptor is β-hydroxybutyrate, a ketone body whose levels rise during fasting. In wild-type animals, 24-hour fasting increased AgRP-ir in adrenal chromaffin cells but this effect was absent in GPR109A knockout mice. GPR109A agonists increased AgRP-ir in isolated chromaffin cells through a GPR109A- and pertussis toxin-sensitive pathway. Incubation of adrenal slices in nicotinic acid, a GPR109A agonist, mimicked the fasting-induced increase in the strength of the preganglionic → chromaffin cell synapse. Finally, reverse transcription polymerase chain reaction experiments confirmed the mouse adrenal medulla contains GPR109A messenger RNA. These results are consistent with the activation of a GPR109A signaling pathway located within the adrenal gland. Because fasting evokes epinephrine release, which stimulates lipolysis and the production of β-hydroxybutyrate, our results indicate that chromaffin cells are components of an autonomic-adipose-hepatic feedback circuit. Coupling a change in adrenal physiology to a metabolite whose levels rise during fasting is presumably an efficient way to coordinate the homeostatic response to food deprivation.
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Affiliation(s)
- Rajesh Gupta
- Department of Cell Biology & Anatomy, LSU Health Sciences Center, New Orleans, Louisiana 70112, USA
| | - Manqi Wang
- Department of Cell Biology & Anatomy, LSU Health Sciences Center, New Orleans, Louisiana 70112, USA
| | - Yunbing Ma
- Department of Cell Biology & Anatomy, LSU Health Sciences Center, New Orleans, Louisiana 70112, USA
| | - Stefan Offermanns
- Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Matthew D Whim
- Correspondence: Matthew D. Whim, PhD, Department of Cell Biology and Anatomy, LSU Health Sciences Center, Medical Education Bldg (MEB 6142), 1901 Perdido St, New Orleans, LA 70112, USA.
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Wang D, Yin J, Zhou Z, Tao Y, Jia Y, Jie H, Zhao J, Li R, Li Y, Guo C, Zhu F, Mao H, Zhang L, Wang Q. Oral Spermidine Targets Brown Fat and Skeletal Muscle to Mitigate Diet-Induced Obesity and Metabolic Disorders. Mol Nutr Food Res 2021; 65:e2100315. [PMID: 34363644 DOI: 10.1002/mnfr.202100315] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/29/2021] [Indexed: 01/09/2023]
Abstract
INTRODUCTION Obesity causes many life-threatening diseases. It is important to develop effective approaches for obesity treatment. Oral supplementation with spermidine retards age-related processes, but its influences on obesity and various metabolic tissues remain largely unknow. This study aims to investigate the effects of oral spermidine on brown adipose tissue (BAT) and skeletal muscle as well as its roles in counteracting obesity and metabolic disorders. METHODS AND RESULTS Spermidine is orally administrated into high-fat diet (HFD)-fed mice. The weight gain, insulin resistance, and hepatic steatosis are attenuated by oral spermidine in HFD-fed mice, accompanied by an alleviation of white adipose tissue inflammation. Oral spermidine promotes BAT activation and metabolic adaptation of skeletal muscle in HFD-fed mice, evidenced by UCP-1 induction and CREB activation in both tissues. Notably, oral spermidine upregulates tyrosine hydroxylase in hypothalamus of HFD-fed mice; spermidine treatment increases tyrosine hydroxylase expression and norepinephrine production in neurocytes, which leads to CREB activation and UCP-1 induction in brown adipocytes and myotubes. Spermidine also directly promotes UCP-1 and PGC-1α expression in brown adipocytes and myotubes. CONCLUSION Spermidine serves as an oral supplement to attenuate obesity and metabolic disorders through hypothalamus-dependent or -independent BAT activation and skeletal muscle adaptation.
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Affiliation(s)
- Di Wang
- Key Laboratory of Infection and Immunity of Shandong Province, Shandong Provincial Clinical Research Center for Immune Diseases and Gout, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Jilong Yin
- Key Laboratory of Infection and Immunity of Shandong Province, Shandong Provincial Clinical Research Center for Immune Diseases and Gout, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Zixin Zhou
- Key Laboratory of Infection and Immunity of Shandong Province, Shandong Provincial Clinical Research Center for Immune Diseases and Gout, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yan Tao
- Key Laboratory of Infection and Immunity of Shandong Province, Shandong Provincial Clinical Research Center for Immune Diseases and Gout, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yufeng Jia
- Key Laboratory of Infection and Immunity of Shandong Province, Shandong Provincial Clinical Research Center for Immune Diseases and Gout, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Haipeng Jie
- Key Laboratory of Infection and Immunity of Shandong Province, Shandong Provincial Clinical Research Center for Immune Diseases and Gout, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Jingyuan Zhao
- Key Laboratory of Infection and Immunity of Shandong Province, Shandong Provincial Clinical Research Center for Immune Diseases and Gout, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Ruiyu Li
- Key Laboratory of Infection and Immunity of Shandong Province, Shandong Provincial Clinical Research Center for Immune Diseases and Gout, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yuan Li
- Key Laboratory of Infection and Immunity of Shandong Province, Shandong Provincial Clinical Research Center for Immune Diseases and Gout, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Chun Guo
- Key Laboratory of Infection and Immunity of Shandong Province, Shandong Provincial Clinical Research Center for Immune Diseases and Gout, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Faliang Zhu
- Key Laboratory of Infection and Immunity of Shandong Province, Shandong Provincial Clinical Research Center for Immune Diseases and Gout, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Haiting Mao
- Department of Clinical Laboratory, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Lining Zhang
- Key Laboratory of Infection and Immunity of Shandong Province, Shandong Provincial Clinical Research Center for Immune Diseases and Gout, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Qun Wang
- Key Laboratory of Infection and Immunity of Shandong Province, Shandong Provincial Clinical Research Center for Immune Diseases and Gout, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
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Raje V, Ahern KW, Martinez BA, Howell NL, Oenarto V, Granade ME, Kim JW, Tundup S, Bottermann K, Gödecke A, Keller SR, Kadl A, Bland ML, Harris TE. Adipocyte lipolysis drives acute stress-induced insulin resistance. Sci Rep 2020; 10:18166. [PMID: 33097799 PMCID: PMC7584576 DOI: 10.1038/s41598-020-75321-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 10/09/2020] [Indexed: 12/12/2022] Open
Abstract
Stress hyperglycemia and insulin resistance are evolutionarily conserved metabolic adaptations to severe injury including major trauma, burns, or hemorrhagic shock (HS). In response to injury, the neuroendocrine system increases secretion of counterregulatory hormones that promote rapid mobilization of nutrient stores, impair insulin action, and ultimately cause hyperglycemia, a condition known to impair recovery from injury in the clinical setting. We investigated the contributions of adipocyte lipolysis to the metabolic response to acute stress. Both surgical injury with HS and counterregulatory hormone (epinephrine) infusion profoundly stimulated adipocyte lipolysis and simultaneously triggered insulin resistance and hyperglycemia. When lipolysis was inhibited, the stress-induced insulin resistance and hyperglycemia were largely abolished demonstrating an essential requirement for adipocyte lipolysis in promoting stress-induced insulin resistance. Interestingly, circulating non-esterified fatty acid levels did not increase with lipolysis or correlate with insulin resistance during acute stress. Instead, we show that impaired insulin sensitivity correlated with circulating levels of the adipokine resistin in a lipolysis-dependent manner. Our findings demonstrate the central importance of adipocyte lipolysis in the metabolic response to injury. This insight suggests new approaches to prevent insulin resistance and stress hyperglycemia in trauma and surgery patients and thereby improve outcomes.
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Affiliation(s)
- Vidisha Raje
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Katelyn W Ahern
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Brittany A Martinez
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Nancy L Howell
- Department of Medicine, Endocrinology and Metabolism, University of Virginia, Charlottesville, VA, USA
| | - Vici Oenarto
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.,Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Mitchell E Granade
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Jae Woo Kim
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Smanla Tundup
- Department of Medicine, Pulmonary and Critical Care Medicine, University of Virginia, Charlottesville, VA, USA
| | | | - Axel Gödecke
- Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Susanna R Keller
- Department of Medicine, Endocrinology and Metabolism, University of Virginia, Charlottesville, VA, USA
| | - Alexandra Kadl
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.,Department of Medicine, Pulmonary and Critical Care Medicine, University of Virginia, Charlottesville, VA, USA
| | - Michelle L Bland
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Thurl E Harris
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.
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Jall S, De Angelis M, Lundsgaard AM, Fritzen AM, Nicolaisen TS, Klein AB, Novikoff A, Sachs S, Richter EA, Kiens B, Schramm KW, Tschöp MH, Stemmer K, Clemmensen C, Müller TD, Kleinert M. Pharmacological targeting of α3β4 nicotinic receptors improves peripheral insulin sensitivity in mice with diet-induced obesity. Diabetologia 2020; 63:1236-1247. [PMID: 32140744 PMCID: PMC7228898 DOI: 10.1007/s00125-020-05117-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 01/31/2020] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Treatment with the α3β4 nicotinic acetylcholine receptor (nAChR) agonist, 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), improves glucose tolerance in diet-induced obese (DIO) mice, but the physiological and molecular mechanisms are unknown. METHODS DMPP (10 mg/kg body weight, s.c.) was administered either in a single injection (acute) or daily for up to 14 days (chronic) in DIO wild-type (WT) and Chrnb4 knockout (KO) mice and glucose tolerance, tissue-specific tracer-based glucose metabolism, and insulin signalling were assessed. RESULTS In WT mice, but not in Chrnb4 KO mice, single acute treatment with DMPP induced transient hyperglycaemia, which was accompanied by high plasma adrenaline (epinephrine) levels, upregulated hepatic gluconeogenic genes, and decreased hepatic glycogen content. In contrast to these acute effects, chronic DMPP treatment in WT mice elicited improvements in glucose tolerance already evident after three consecutive days of DMPP treatment. After seven days of DMPP treatment, glucose tolerance was markedly improved, also in comparison with mice that were pair-fed to DMPP-treated mice. The glycaemic benefit of chronic DMPP was absent in Chrnb4 KO mice. Chronic DMPP increased insulin-stimulated glucose clearance into brown adipose tissue (+69%), heart (+93%), gastrocnemius muscle (+74%) and quadriceps muscle (+59%), with no effect in white adipose tissues. After chronic DMPP treatment, plasma adrenaline levels did not increase following an injection with DMPP. In glucose-stimulated skeletal muscle, we detected a decreased phosphorylation of the inhibitory Ser640 phosphorylation site on glycogen synthase and a congruent increase in glycogen accumulation following chronic DMPP treatment. CONCLUSIONS/INTERPRETATION Our data suggest that DMPP acutely induces adrenaline release and hepatic glycogenolysis, while chronic DMPP-mediated activation of β4-containing nAChRs improves peripheral insulin sensitivity independently of changes in body weight via mechanisms that could involve increased non-oxidative glucose disposal into skeletal muscle.
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Affiliation(s)
- Sigrid Jall
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
- Division of Metabolic Diseases, TUM School of Medicine, Technische Universität München, Munich, Germany
| | - Meri De Angelis
- Molecular EXposomics (MEX) at Helmholtz Zentrum München, Neuherberg, Germany
| | - Anne-Marie Lundsgaard
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Andreas M Fritzen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Trine S Nicolaisen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen N, Denmark
| | - Anders B Klein
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen N, Denmark
| | - Aaron Novikoff
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
- Division of Metabolic Diseases, TUM School of Medicine, Technische Universität München, Munich, Germany
| | - Stephan Sachs
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
- Division of Metabolic Diseases, TUM School of Medicine, Technische Universität München, Munich, Germany
- Institute of Diabetes and Regeneration Research, Helmholtz Diabetes Center at Helmholtz Zentrum München, Neuherberg, Germany
| | - Erik A Richter
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Bente Kiens
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Karl-Werner Schramm
- Molecular EXposomics (MEX) at Helmholtz Zentrum München, Neuherberg, Germany
- Department für Biowissenschaften, Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt, Technische Universität München, Freising, Germany
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
- Division of Metabolic Diseases, TUM School of Medicine, Technische Universität München, Munich, Germany
- Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Munich-Neuherberg, Germany
| | - Kerstin Stemmer
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Christoffer Clemmensen
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany.
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen N, Denmark.
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany.
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany.
| | - Maximilian Kleinert
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany.
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.
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Pedersen C, Kraft G, Edgerton DS, Scott M, Farmer B, Smith M, Laneve DC, Williams PE, Moore LM, Cherrington AD. The kinetics of glucagon action on the liver during insulin-induced hypoglycemia. Am J Physiol Endocrinol Metab 2020; 318:E779-E790. [PMID: 32208001 PMCID: PMC7272728 DOI: 10.1152/ajpendo.00466.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glucagon's effect on hepatic glucose production (HGP), under hyperglycemic conditions, is time dependent such that after an initial burst of HGP, it slowly wanes. It is not known whether this is also the case under hypoglycemic conditions, where an increase in HGP is essential. This question was addressed using adrenalectomized dogs to avoid the confounding effects of other counterregulatory hormones. During the study, infusions of epinephrine and cortisol were given to maintain basal levels. Somatostatin and insulin (800 µU·kg-1·min-1) were infused to induce hypoglycemia. After 30 min, glucagon was infused at a basal rate (1 ng·kg-1·min-1, baGGN group, n = 5 dogs) or a rate eightfold basal (8 ng·kg-1·min-1, hiGGN group, n = 5 dogs) for 4 h. Glucose was infused to match the arterial glucose levels between groups (≈50 mg/dL). Our data showed that glucagon has a biphasic effect on the liver despite hypoglycemia. Hyperglucagonemia stimulated a rapid, transient peak in HGP (4-fold basal production) over ~60 min, which was followed by a slow reduction in HGP to a rate 1.5-fold basal. During the last 2 h of the experiment, hiGGN stimulated glucose production at a rate fivefold greater than baGGN (2.5 vs. 0.5 mg·kg-1·min-1, respectively), indicating a sustained effect of the hormone. Of note, the hypoglycemia-induced rises in norepinephrine and glycerol were smaller in hiGGN compared with the baGGN group despite identical hypoglycemia. This finding suggests that there is reciprocity between glucagon and the sympathetic nervous system such that when glucagon is increased, the sympathetic nervous response to hypoglycemia is downregulated.
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Affiliation(s)
| | - Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Dale S Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Melanie Scott
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Marta Smith
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - David C Laneve
- Section of Surgical Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Phillip E Williams
- Section of Surgical Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - L Merkle Moore
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
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7
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Ma Y, Wang Q, Joe D, Wang M, Whim MD. Recurrent hypoglycemia inhibits the counterregulatory response by suppressing adrenal activity. J Clin Invest 2018; 128:3866-3871. [PMID: 30080182 DOI: 10.1172/jci91921] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 06/20/2018] [Indexed: 01/02/2023] Open
Abstract
Hypoglycemia activates the counterregulatory response (CRR), a neural-endocrine reflex that restores euglycemia. Although effective if occasionally activated, repeated induction of the CRR leads to a decline in responsiveness and prolonged exposure to hypoglycemia. The mechanism underlying this impairment is not known. We found that the reduction in epinephrine release that characterizes a suppressed CRR involves a long-lasting form of sympatho-adrenal synaptic plasticity. Using optogenetically evoked catecholamine release, we show that recurrent hypoglycemia reduced the secretory capacity of mouse adrenal chromaffin cells. Single activation of the CRR increased the adrenal levels of tyrosine hydroxylase (TH), the rate-limiting enzyme for catecholamine synthesis, but this was prevented by repeated activation. In contrast, the level of neuropeptide Y (NPY), an adrenal cotransmitter, remained elevated after recurrent hypoglycemia. Inhibition of NPY or Y1 signaling, either transgenically or pharmacologically, prevented the attenuation of both TH expression and epinephrine release. These results indicate that impairment of the CRR involves suppressed activity at the adrenal level. Interfering with the peripheral NPY-dependent negative feedback loop may provide a way to avoid the pathophysiological consequences of recurrent hypoglycemia which are common in the diabetic state.
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Gregory JM, Rivera N, Kraft G, Winnick JJ, Farmer B, Allen EJ, Donahue EP, Smith MS, Edgerton DS, Williams PE, Cherrington AD. Glucose autoregulation is the dominant component of the hormone-independent counterregulatory response to hypoglycemia in the conscious dog. Am J Physiol Endocrinol Metab 2017; 313:E273-E283. [PMID: 28512154 PMCID: PMC5625082 DOI: 10.1152/ajpendo.00099.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/04/2017] [Accepted: 05/09/2017] [Indexed: 12/26/2022]
Abstract
The contribution of hormone-independent counterregulatory signals in defense of insulin-induced hypoglycemia was determined in adrenalectomized, overnight-fasted conscious dogs receiving hepatic portal vein insulin infusions at a rate 20-fold basal. Either euglycemia was maintained (group 1) or hypoglycemia (≈45 mg/dl) was allowed to occur. There were three hypoglycemic groups: one in which hepatic autoregulation against hypoglycemia occurred in the absence of sympathetic nervous system input (group 2), one in which autoregulation occurred in the presence of norepinephrine (NE) signaling to fat and muscle (group 3), and one in which autoregulation occurred in the presence of NE signaling to fat, muscle, and liver (group 4). Average net hepatic glucose balance (NHGB) during the last hour for groups 1-4 was -0.7 ± 0.1, 0.3 ± 0.1 (P < 0.01 vs. group 1), 0.7 ± 0.1 (P = 0.01 vs. group 2), and 0.8 ± 0.1 (P = 0.7 vs. group 3) mg·kg-1·min-1, respectively. Hypoglycemia per se (group 2) increased NHGB by causing an inhibition of net hepatic glycogen synthesis. NE signaling to fat and muscle (group 3) increased NHGB further by mobilizing gluconeogenic precursors resulting in a rise in gluconeogenesis. Lowering glucose per se decreased nonhepatic glucose uptake by 8.9 mg·kg-1·min-1, and the addition of increased neural efferent signaling to muscle and fat blocked glucose uptake further by 3.2 mg·kg-1·min-1 The addition of increased neural efferent input to liver did not affect NHGB or nonhepatic glucose uptake significantly. In conclusion, even in the absence of increases in counterregulatory hormones, the body can defend itself against hypoglycemia using glucose autoregulation and increased neural efferent signaling, both of which stimulate hepatic glucose production and limit glucose utilization.
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Affiliation(s)
- Justin M Gregory
- Vanderbilt Ian Burr Division of Pediatric Endocrinology and Diabetes, Vanderbilt University School of Medicine, Nashville, Tennessee;
| | - Noelia Rivera
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee; and
| | - Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee; and
| | - Jason J Winnick
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee; and
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee; and
| | - Eric J Allen
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee; and
| | - E Patrick Donahue
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee; and
| | - Marta S Smith
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee; and
| | - Dale S Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee; and
| | - Phillip E Williams
- Section of Surgical Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee; and
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Gupta R, Ma Y, Wang M, Whim MD. AgRP-Expressing Adrenal Chromaffin Cells Are Involved in the Sympathetic Response to Fasting. Endocrinology 2017; 158:2572-2584. [PMID: 28531318 PMCID: PMC5551550 DOI: 10.1210/en.2016-1268] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 05/16/2017] [Indexed: 01/23/2023]
Abstract
Fasting evokes a homeostatic response that maintains circulating levels of energy-rich metabolites and increases the drive to eat. Centrally, this reflex activates a small population of hypothalamic neurons that are characterized by the expression of AgRP, a neuropeptide with an extremely restricted distribution. Apart from the hypothalamus, the only other site with substantial expression is the adrenal gland, but there is disagreement about which cells synthesize AgRP. Using immunohistochemistry, flow cytometry, and reverse transcription-polymerase chain reaction, we show AgRP is present in the mouse adrenal medulla and is expressed by neuroendocrine chromaffin cells that also synthesize the catecholamines and neuropeptide Y. Short-term fasting led to an increase in adrenal AgRP expression. Because AgRP can act as an antagonist at MC3/4 receptors, we tested whether melanotan II, an MC3/4 receptor agonist, could regulate pre- and postsynaptic signaling within the adrenal medulla. Melanotan II decreased the paired-pulse ratio of evoked synaptic currents recorded in chromaffin cells; this effect was blocked by exogenous AgRP. In contrast, neither melanotan II nor AgRP altered the optogenetically evoked release of catecholamines from isolated chromaffin cells. These results are consistent with the idea that AgRP regulates the strength of the sympathetic input by modulation of presynaptic MC3/4 receptors located on preganglionic neurons. We conclude that a small population of neuroendocrine cells in the adrenal medulla, and the arcuate nucleus of the hypothalamus, express AgRP and neuropeptide Y and are functionally involved in the systemic response to fasting.
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Affiliation(s)
- Rajesh Gupta
- Department of Cell Biology & Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | - Yunbing Ma
- Department of Cell Biology & Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | - Manqi Wang
- Department of Cell Biology & Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | - Matthew D. Whim
- Department of Cell Biology & Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
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10
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Fasting induces a form of autonomic synaptic plasticity that prevents hypoglycemia. Proc Natl Acad Sci U S A 2016; 113:E3029-38. [PMID: 27092009 DOI: 10.1073/pnas.1517275113] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
During fasting, activation of the counter-regulatory response (CRR) prevents hypoglycemia. A major effector arm is the autonomic nervous system that controls epinephrine release from adrenal chromaffin cells and, consequently, hepatic glucose production. However, whether modulation of autonomic function determines the relative strength of the CRR, and thus the ability to withstand food deprivation and maintain euglycemia, is not known. Here we show that fasting leads to altered transmission at the preganglionic → chromaffin cell synapse. The dominant effect is a presynaptic, long-lasting increase in synaptic strength. Using genetic and pharmacological approaches we show this plasticity requires neuropeptide Y, an adrenal cotransmitter and the activation of adrenal Y5 receptors. Loss of neuropeptide Y prevents a fasting-induced increase in epinephrine release and results in hypoglycemia in vivo. These findings connect plasticity within the sympathetic nervous system to a physiological output and indicate the strength of the final synapse in this descending pathway plays a decisive role in maintaining euglycemia.
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12
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Leti T, Guinot M, Favre-Juvin A, Bricout VA. Difference of catecholamine responses to exercise in men with trisomy 21, with or without chronotropic incompetence. Physiol Behav 2015; 142:97-103. [PMID: 25660758 DOI: 10.1016/j.physbeh.2015.02.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 01/30/2015] [Accepted: 02/03/2015] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Our purpose was to analyse if catecholamine responses to exercise would be different in Down syndrome (DS) with or without chronotropic incompetence. RESEARCH DESIGN AND METHODS Twenty five men with DS (mean age 22.2 ± 3.2) and twenty six controls (CONT, mean age 22.5 ± 1.4) participated in the study, and are divided into 3 groups: CONT, DS with chronotropic incompetence (DS+) and DS without chronotropic incompetence (DS-). During two treadmill incremental tests, blood samples were collected for the determination of hormonal and metabolic variables. RESULTS Ten out of 25 DS had chronotropic incompetence whereas no CONT. At rest, compared to CONT, despite similar physical activity, DS with chronotropic incompetence had significantly higher subcutaneous fat mass (p<0.001), lower epinephrine concentration (p<0.01), and higher leptin (p<0.01) and insulin concentrations (p<0.05). At peak exercise, all DS had lower heart rate, oxygen uptake and blood lactate concentrations than controls (p<0.001). During a 'Submaximal incremental test', DS with chronotropic incompetence had lower HR and lactate values (p<0.001) compared to CONT and DS without chronotropic incompetence (p<0.01). They also had blunted epinephrine and impaired norepinephrine responses to exercise compared to DS without chronotropic incompetence and CONT (p<0.01 and p<0.05 respectively). CONCLUSIONS Our results indicate that catecholamine adaptations to exercise are not adequate in DS+ and are associated with exercise intolerance. Thus, this endocrine profile at rest and during exercise may limit endurance performance of DS.
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Affiliation(s)
- T Leti
- Univ. Grenoble Alpes, HP2, F-38000 Grenoble, France; INSERM U1042, HP2, F-38000 Grenoble, France
| | - M Guinot
- INSERM U1042, HP2, F-38000 Grenoble, France; CHU de Grenoble, Cardiovascular & Thoracic Unit; Sports & Pathologies, F-38000 Grenoble, France
| | - A Favre-Juvin
- CHU de Grenoble, Cardiovascular & Thoracic Unit; Sports & Pathologies, F-38000 Grenoble, France
| | - V-A Bricout
- Univ. Grenoble Alpes, HP2, F-38000 Grenoble, France; INSERM U1042, HP2, F-38000 Grenoble, France; CHU de Grenoble, Cardiovascular & Thoracic Unit; Sports & Pathologies, F-38000 Grenoble, France.
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13
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Vu CU, Siddiqui JA, Wadensweiler P, Gayen JR, Avolio E, Bandyopadhyay GK, Biswas N, Chi NW, O'Connor DT, Mahata SK. Nicotinic acetylcholine receptors in glucose homeostasis: the acute hyperglycemic and chronic insulin-sensitive effects of nicotine suggest dual opposing roles of the receptors in male mice. Endocrinology 2014; 155:3793-805. [PMID: 25051446 DOI: 10.1210/en.2014-1320] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cigarette smoking causes insulin resistance. However, nicotine induces anti-inflammation and improves glucose tolerance in insulin-resistant animal models. Here, we determined the effects of nicotine on glucose metabolism in insulin-sensitive C57BL/J6 mice. Acute nicotine administration (30 min) caused fasting hyperglycemia and lowered insulin sensitivity acutely, which depended on the activation of nicotinic-acetylcholine receptors (nAChRs) and correlated with increased catecholamine secretion, nitric oxide (NO) production, and glycogenolysis. Chlorisondamine, an inhibitor of nAChRs, reduced acute nicotine-induced hyperglycemia. qRT-PCR analysis revealed that the liver and muscle express predominantly β4 > α10 > α3 > α7 and β4 > α10 > β1 > α1 mRNA for nAChR subunits respectively, whereas the adrenal gland expresses β4 > α3 > α7 > α10 mRNA. Chronic nicotine treatment significantly suppressed expression of α3-nAChR (predominant peripheral α-subunit) in liver. Whereas acute nicotine treatment raised plasma norepinephrine (NE) and epinephrine (Epi) levels, chronic nicotine exposure raised only Epi. Acute nicotine treatment raised both basal and glucose-stimulated insulin secretion (GSIS). After chronic nicotine treatment, basal insulin level was elevated, but GSIS after acute saline or nicotine treatment was blunted. Chronic nicotine exposure caused an increased buildup of NO in plasma and liver, leading to decreased glycogen storage, along with a concomitant suppression of Pepck and G6Pase mRNA, thus preventing hyperglycemia. The insulin-sensitizing effect of chronic nicotine was independent of weight loss. Chronic nicotine treatment enhanced PI-3-kinase activities and increased Akt and glycogen synthase kinase (GSK)-3β phosphorylation in an nAChR-dependent manner coupled with decreased cAMP response element-binding protein (CREB) phosphorylation. The latter effects caused suppression of Pepck and G6Pase gene expression. Thus, nicotine causes both insulin resistance and insulin sensitivity depending on the duration of the treatment.
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Affiliation(s)
- Christine U Vu
- VA San Diego Healthcare System (C.U.V., P.W., J.R.G., G.K.B., N.-W.C., D.T.O'C., S.K.M.), San Diego, California 92161; and Department of Medicine (J.A.S., E.A., G.K.B., N.B., N.-W.C., S.K.M.), University of California, San Diego, California 92093
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Blanco CL, McGill-Vargas LL, McCurnin D, Quinn AR. Hyperglycemia increases the risk of death in extremely preterm baboons. Pediatr Res 2013; 73:337-43. [PMID: 23364173 PMCID: PMC4112412 DOI: 10.1038/pr.2012.184] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Transient neonatal hyperglycemia (HG) has been reported in up to 80% of extremely preterm human infants. We hypothesize that severe HG is associated with increased morbidity and mortality in preterm baboons. METHODS Sixty-six baboons born at 67% of gestation were studied. HG was defined as serum glucose level ≥150 mg/dl during the first week of life. Animals were stratified into two groups: severe HG (≥8 events) and nonsevere HG (<8 events). RESULTS HG developed in 65 of the 66 (98%) baboons that were included. A total of 3,386 glucose measurements were obtained. The mean serum glucose level was 159 ± 69 mg/dl for the severe HG group and 130 ± 48 mg/dl for the nonsevere HG group during the first week of life. No differences were found in gender, birth weight, sepsis, patent ductus arteriosus, or oxygenation/ventilation indexes between groups. Severe HG was associated with early death even after controlling for sepsis, postnatal steroid exposure, and catecholamine utilization. CONCLUSION HG is common in preterm baboons and is not associated with short-term morbidity. Severe HG occurring in the first week of life is associated with early death in preterm baboons.
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Affiliation(s)
- Cynthia L. Blanco
- Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA,Corresponding Author: 7703 Floyd Curl Drive, MC-7812 San Antonio, TX, 78229 phone: 210-567-5225, fax: 210-567-5169
| | - Lisa L. McGill-Vargas
- Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Donald McCurnin
- Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Amy R. Quinn
- Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
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Emhoff CAW, Messonnier LA, Horning MA, Fattor JA, Carlson TJ, Brooks GA. Gluconeogenesis and hepatic glycogenolysis during exercise at the lactate threshold. J Appl Physiol (1985) 2012; 114:297-306. [PMID: 23239870 DOI: 10.1152/japplphysiol.01202.2012] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Because the maintenance of glycemia is essential during prolonged exercise, we examined the effects of endurance training, exercise intensity, and plasma lactate concentration ([lactate]) on gluconeogenesis (GNG) and hepatic glycogenolysis (GLY) in fasted men exercising at, and just below, the lactate threshold (LT), where GNG precursor lactate availability is high. Twelve healthy men (6 untrained, 6 trained) completed 60 min of constant-load exercise at power outputs corresponding to their individual LT. Trained subjects completed two additional 60-min sessions of constant-load exercise: one at 10% below the LT workload (LT-10%), and the other with a lactate clamp (LT-10%+LC) to match the [lactate] of the LT trial. Flux rates were determined by primed continuous infusion of [6,6-(2)H(2)]glucose, [3-(13)C]lactate, and [(13)C]bicarbonate tracers during 90 min of rest and 60 min of cycling. Exercise at LT corresponded to 67.6 ± 1.3 and 74.8 ± 1.7% peak O(2) consumption in the untrained and trained subjects, respectively (P < 0.05). Relative exercise intensity was matched between the untrained group at LT and the trained group at LT-10%, and [lactate] during exercise was matched in the LT and LT-10%+LC trials via exogenous lactate infusion. Glucose kinetics (rate of appearance, rate of disposal, and metabolic clearance rate) were augmented with the lactate clamp. GNG was decreased in the trained subjects exercising at LT and LT-10% compared with the untrained subjects, but increasing [lactate] in the LT-10%+LC trial significantly increased GNG (4.4 ± 0.9 mg·kg(-1)·min(-1)) compared with its corresponding control (1.7 ± 0.4 mg·kg(-1)·min(-1), P < 0.05). Hepatic GLY was higher in the trained than untrained subjects, but not significantly different across conditions. We conclude that GNG plays an essential role in maintaining total glucose production during exercise in fasted men, regardless of training state. However, endurance training increases the ability to achieve a higher relative exercise intensity and absolute power output at the LT without a significant decrease in GNG. Furthermore, raising systemic precursor substrate availability increases GNG during exercise, but not at rest.
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Affiliation(s)
- Chi-An W Emhoff
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA 94720-3140, USA
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16
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Virtue S, Feldmann H, Christian M, Tan CY, Masoodi M, Dale M, Lelliott C, Burling K, Campbell M, Eguchi N, Voshol P, Sethi JK, Parker M, Urade Y, Griffin JL, Cannon B, Vidal-Puig A. A new role for lipocalin prostaglandin d synthase in the regulation of brown adipose tissue substrate utilization. Diabetes 2012; 61:3139-47. [PMID: 22923471 PMCID: PMC3501861 DOI: 10.2337/db12-0015] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 06/13/2012] [Indexed: 01/10/2023]
Abstract
In this study, we define a new role for lipocalin prostaglandin D synthase (L-PGDS) in the control of metabolic fuel utilization by brown adipose tissue (BAT). We demonstrate that L-PGDS expression in BAT is positively correlated with BAT activity, upregulated by peroxisome proliferator-activated receptor γ coactivator 1α or 1β and repressed by receptor-interacting protein 140. Under cold-acclimated conditions, mice lacking L-PGDS had elevated reliance on carbohydrate to provide fuel for thermogenesis and had increased expression of genes regulating glycolysis and de novo lipogenesis in BAT. These transcriptional differences were associated with increased lipid content in BAT and a BAT lipid composition enriched with de novo synthesized lipids. Consistent with the concept that lack of L-PGDS increases glucose utilization, mice lacking L-PGDS had improved glucose tolerance after high-fat feeding. The improved glucose tolerance appeared to be independent of changes in insulin sensitivity, as insulin levels during the glucose tolerance test and insulin, leptin, and adiponectin levels were unchanged. Moreover, L-PGDS knockout mice exhibited increased expression of genes involved in thermogenesis and increased norepinephrine-stimulated glucose uptake to BAT, suggesting that sympathetically mediated changes in glucose uptake may have improved glucose tolerance. Taken together, these results suggest that L-PGDS plays an important role in the regulation of glucose utilization in vivo.
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Affiliation(s)
- Sam Virtue
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Treatment Centre, Addenbrooke’s Hospital, Cambridge, U.K
| | - Helena Feldmann
- Wenner-Gren Institute, University of Stockholm, Stockholm, Sweden
| | - Mark Christian
- Molecular Endocrinology Laboratory, Institute of Reproductive and Developmental Biology, Imperial College London, London, U.K
| | - Chong Yew Tan
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Treatment Centre, Addenbrooke’s Hospital, Cambridge, U.K
| | - Mojgan Masoodi
- Human Nutrition Research and the Department of Biochemistry, Medical Research Council, Cambridge, U.K
| | - Martin Dale
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Treatment Centre, Addenbrooke’s Hospital, Cambridge, U.K
| | - Chris Lelliott
- Department of Research and Development, AstraZeneca, Mölndal, Sweden
| | - Keith Burling
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Treatment Centre, Addenbrooke’s Hospital, Cambridge, U.K
| | - Mark Campbell
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Treatment Centre, Addenbrooke’s Hospital, Cambridge, U.K
| | | | - Peter Voshol
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Treatment Centre, Addenbrooke’s Hospital, Cambridge, U.K
| | - Jaswinder K. Sethi
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Treatment Centre, Addenbrooke’s Hospital, Cambridge, U.K
| | - Malcolm Parker
- Molecular Endocrinology Laboratory, Institute of Reproductive and Developmental Biology, Imperial College London, London, U.K
| | | | - Julian L. Griffin
- Human Nutrition Research and the Department of Biochemistry, Medical Research Council, Cambridge, U.K
| | - Barbara Cannon
- Wenner-Gren Institute, University of Stockholm, Stockholm, Sweden
| | - Antonio Vidal-Puig
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Treatment Centre, Addenbrooke’s Hospital, Cambridge, U.K
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Abstract
Glucagon is a primary regulator of hepatic glucose production (HGP) in vivo during fasting, exercise and hypoglycaemia. Glucagon also plays a role in limiting hepatic glucose uptake and producing the hyperglycaemic phenotype associated with insulin deficiency and insulin resistance. In response to a physiological rise in glucagon, HGP is rapidly stimulated. This increase in HGP is entirely attributable to an enhancement of glycogenolysis, with little to no acute effect on gluconeogenesis. This dramatic rise in glycogenolysis in response to hyperglucagonemia wanes with time. A component of this waning effect is known to be independent of hyperglycemia, though the molecular basis for this tachyphylaxis is not fully understood. In the overnight fasted state, the presence of basal glucagon secretion is essential in countering the suppressive effects of basal insulin, resulting in the maintenance of appropriate levels of glycogenolysis, fasting HGP and blood glucose. The enhancement of glycogenolysis in response to elevated glucagon is critical in the life-preserving counterregulatory response to hypoglycaemia, as well as a key factor in providing adequate circulating glucose for working muscle during exercise. Finally, glucagon has a key role in promoting the catabolic consequences associated with states of deficient insulin action, which supports the therapeutic potential in developing glucagon receptor antagonists or inhibitors of glucagon secretion.
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Affiliation(s)
- C J Ramnanan
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-0615, USA
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18
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Sprague JE, Arbeláez AM. Glucose counterregulatory responses to hypoglycemia. PEDIATRIC ENDOCRINOLOGY REVIEWS : PER 2011; 9:463-73; quiz 474-5. [PMID: 22783644 PMCID: PMC3755377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The brain relies almost exclusively on glucose for fuel. Therefore, adequate uptake of glucose from the plasma is key for normal brain function and survival. Despite wide variations in glucose flux (i.e., fed state, fasting state, etc), blood glucose is maintained in a very narrow range. This is accomplished by a series of hormonal and physiologic responses. As a result, hypoglycemia is a rare occurrence in normal individuals. However, glucose counterregulatory responses are altered in patients with diabetes treated with insulin especially after repeated hypoglycemia or antecedent exercise.
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Affiliation(s)
- Jennifer E Sprague
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Horton TJ, Dow S, Armstrong M, Donahoo WT. Greater systemic lipolysis in women compared with men during moderate-dose infusion of epinephrine and/or norepinephrine. J Appl Physiol (1985) 2009; 107:200-10. [PMID: 19407251 DOI: 10.1152/japplphysiol.90812.2008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Women have lower circulating catecholamine levels during metabolic perturbations, such as exercise or hypoglycemia, but similar rates of systemic lipolysis. This suggests women may be more sensitive to the lipolytic action of catecholamines, while maintaining similar glucoregulatory effects. The aim of the present study, therefore, was to determine whether women have higher rates of systemic lipolysis compared with men in response to matched peripheral infusion of catecholamines, but similar rates of glucose turnover. Healthy, nonobese women (n = 11) and men (n = 10) were recruited and studied on 3 separate days with the following infusions: epinephrine (Epi), norepinephrine (NE), or the two combined. Tracer infusions of glycerol and glucose were used to determine systemic lipolysis and glucose turnover, respectively. Following basal measurements of substrate kinetics, the catecholamine infusion commenced, and measures of substrate kinetics continued for 60 min. Catecholamine concentrations were similarly elevated in women and men during each infusion: Epi, 182-197 pg/ml and NE, 417-507 pg/ml. There was a significant sex difference in glycerol rate of appearance and rate of disappearance with the catecholamine infusions (P < 0.0001), mainly due to a significantly greater glycerol turnover during the first 30 min of each infusion: glycerol rate of appearance during Epi was only 268 +/- 18 vs. 206 +/- 21 micromol/min in women and men, respectively; during NE, only 173 +/- 13 vs. 153 +/- 17 micromol/min, and during Epi+NE, 303 +/- 24 vs. 257 +/- 21 micromol/min. No sex differences were observed in glucose kinetics under any condition. In conclusion, these data suggest that women are more sensitive to the lipolytic action of catecholamines, but have no difference in their glucoregulatory response. Thus the lower catcholamine levels observed in women vs. men during exercise and other metabolic perturbations may allow women to maintain a similar or greater level of lipid mobilization while minimizing changes in glucose turnover.
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Affiliation(s)
- Tracy J Horton
- Section of Nutrition, Dept. of Pediatrics, Univ. of Colorado Denver, Campus Box C225, 12700 East 19th Ave., Aurora, CO 80045, USA.
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Durocher LL, Hinchcliff KW, DiBartola SP, Johnson SE. Acid-base and hormonal abnormalities in dogs with naturally occurring diabetes mellitus. J Am Vet Med Assoc 2008; 232:1310-20. [DOI: 10.2460/javma.232.9.1310] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Moore MC, Dicostanzo CA, Smith MS, Farmer B, Rodewald TD, Neal DW, Williams PE, Cherrington AD. Hepatic portal venous delivery of a nitric oxide synthase inhibitor enhances net hepatic glucose uptake. Am J Physiol Endocrinol Metab 2008; 294:E768-77. [PMID: 18212022 DOI: 10.1152/ajpendo.00184.2007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Hepatic portal venous infusion of nitric oxide synthase (NOS) inhibitors causes muscle insulin resistance, but the effects on hepatic glucose disposition are unknown. Conscious dogs underwent a hyperinsulinemic (4-fold basal) hyperglycemic (hepatic glucose load 2-fold basal) clamp, with assessment of liver metabolism by arteriovenous difference methods. After 90 min (P1), dogs were divided into two groups: control (receiving intraportal saline infusion; n = 8) and LN [receiving N(G)-nitro-L-arginine methyl ester (L-NAME), a nonspecific NOS inhibitor; n = 11] intraportally at 0.3 mg x kg(-1) x min(-1) for 90 min (P2). During the final 60 min of study (P3), L-NAME was discontinued, and five LN dogs received the NO donor SIN-1 intraportally at 6 mug x kg(-1) x min(-1) while six received saline (LN/SIN-1 and LN/SAL, respectively). Net hepatic fractional glucose extraction (NHFE) in control dogs was 0.034 +/- 0.016, 0.039 +/- 0.015, and 0.056 +/- 0.019 during P1, P2, and P3, respectively. NHFE in LN was 0.045 +/- 0.009 and 0.111 +/- 0.007 during P1 and P2, respectively (P < 0.05 vs. control during P2), and 0.087 +/- 0.009 and 0.122 +/- 0.016 (P < 0.05) during P3 in LN/SIN-1 and LN/SAL, respectively. During P2, arterial glucose was 204 +/- 5 vs. 138 +/- 11 mg/dl (P < 0.05) in LN vs. control to compensate for L-NAME's effect on blood flow. Therefore, another group (LNlow; n = 4) was studied in the same manner as LN/SAL, except that arterial glucose was clamped at the same concentrations as in control. NHFE in LNlow was 0.052 +/- 0.008, 0.093 +/- 0.023, and 0.122 +/- 0.021 during P1, P2, and P3, respectively (P < 0.05 vs. control during P2 and P3), with no significant difference in glucose infusion rates. Thus, NOS inhibition enhanced NHFE, an effect partially reversed by SIN-1.
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Affiliation(s)
- Mary Courtney Moore
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-0615, USA.
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Nutrition Support. Crit Care Med 2008. [DOI: 10.1016/b978-032304841-5.50085-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Lin E, Lowry SF. Substrate Metabolism. Surgery 2008. [DOI: 10.1007/978-0-387-68113-9_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Barth E, Albuszies G, Baumgart K, Matejovic M, Wachter U, Vogt J, Radermacher P, Calzia E. Glucose metabolism and catecholamines. Crit Care Med 2007; 35:S508-18. [PMID: 17713401 DOI: 10.1097/01.ccm.0000278047.06965.20] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Until now, catecholamines were the drugs of choice to treat hypotension during shock states. Catecholamines, however, also have marked metabolic effects, particularly on glucose metabolism, and the degree of this metabolic response is directly related to the beta2-adrenoceptor activity of the individual compound used. Under physiologic conditions, infusing catecholamine is associated with enhanced rates of aerobic glycolysis (resulting in adenosine triphosphate production), glucose release (both from glycogenolysis and gluconeogenesis), and inhibition of insulin-mediated glycogenesis. Consequently, hyperglycemia and hyperlactatemia are the hallmarks of this metabolic response. Under pathophysiologic conditions, the metabolic effects of catecholamines are less predictable because of changes in receptor affinity and density and in drug kinetics and the metabolic capacity of the major gluconeogenic organs, both resulting from the disease per se and the ongoing treatment. It is also well-established that shock states are characterized by a hypermetabolic condition with insulin resistance and increased oxygen demands, which coincide with both compromised tissue microcirculatory perfusion and mitochondrial dysfunction. This, in turn, causes impaired glucose utilization and may lead to inadequate glucose supply and, ultimately, metabolic failure. Based on the landmark studies on intensive insulin use, a crucial role is currently attributed to glucose homeostasis. This article reviews the effects of the various catecholamines on glucose utilization, both under physiologic conditions, as well as during shock states. Because, to date (to our knowledge), no patient data are available, results from relevant animal experiments are discussed. In addition, potential strategies are outlined to influence the catecholamine-induced effects on glucose homeostasis.
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Affiliation(s)
- Eberhard Barth
- Sektion Anästhesiologische Pathophysiologie und Verfahrensentwicklung, Universitätsklinikum, Ulm, Germany
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Rivera N, Everett-Grueter CA, Edgerton DS, Rodewald T, Neal DW, Nishimura E, Larsen MO, Jacobsen LO, Kristensen K, Brand CL, Cherrington AD. A Novel Glucagon Receptor Antagonist, NNC 25-0926, Blunts Hepatic Glucose Production in the Conscious Dog. J Pharmacol Exp Ther 2007; 321:743-52. [PMID: 17308040 DOI: 10.1124/jpet.106.115717] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Elevated glucagon is associated with fasting hyperglycemia in type 2 diabetes. We assessed the effects of the glucagon receptor antagonist (2R)-N-[4-({4-(1-cyclohexen-1-yl)[(3,5-dichloroanilino)carbonyl]anilino}methyl)benzoyl]-2-hydroxy-b-alanine (NNC 25-0926) on hepatic glucose production (HPG) in vivo, using arteriovenous difference and tracer techniques in conscious dogs. The experiments consisted of equilibration (-140 to -40 min), control (40-0 min), and experimental [0-180 min, divided into P1 (0-60 min) and P2 (60-180 min)] periods. In P1, NNC 25-0926 was given intragastrically at 0 (veh), 10, 20, 40, or 100 mg/kg, and euglycemia was maintained. In P2, somatostatin, basal intraportal insulin, and 5-fold basal intraportal glucagon (2.5 ng/kg/min) were infused. Arterial plasma insulin levels remained basal throughout the study in all groups. Arterial plasma glucagon levels remained basal during the control period and P1 and then increased to approximately 70 pg/ml in P2 in all groups. Arterial plasma glucose levels were basal in the control period and P1 in all groups. In P2, the arterial glucose level increased to 245+/-22 and 172+/-15 mg/dl in the veh and 10 mg/kg groups, respectively, whereas in the 20, 40, and 100 mg/kg groups, there was no rise in glucose. Net hepatic glucose output was approximately 2 mg/kg/min in all groups during the control period. In P2, it increased by 9.4+/-2 mg/kg/min in the veh group. In the 10, 20, 40, and 100 mg/kg groups, the rise was only 4.1+/-0.9, 1.6+/-0.6, 2.4+/-0.7, and 1.5+/-0.3 mg/kg/min, respectively, due to inhibition of glycogenolysis. In conclusion, NNC 25-0926 effectively blocked the ability of glucagon to increase HGP in the dog.
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Affiliation(s)
- Noelia Rivera
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 704 Robinson Research Bldg., Nashville, TN 37232-0615, USA
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Baker EH, Wood DM, Brennan AL, Clark N, Baines DL, Philips BJ. Hyperglycaemia and pulmonary infection. Proc Nutr Soc 2007; 65:227-35. [PMID: 16923307 DOI: 10.1079/pns2006499] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Pathophysiological stress from acute illness causes metabolic disturbance, including altered hepatic glucose metabolism, increased peripheral insulin resistance and hyperglycaemia. Acute hyperglycaemia is associated with increased morbidity and mortality in patients in intensive care units and patients with acute respiratory disease. The present review will consider mechanisms underlying this association. In normal lungs the glucose concentration of airway secretions is approximately 10-fold lower than that of plasma. Low airway glucose concentrations are maintained against a concentration gradient by active glucose transport. Airway glucose concentrations become elevated if normal homeostasis is disrupted by a rise in blood glucose concentrations or inflammation of the airway epithelium. Elevated airway glucose concentrations are associated with and precede increased isolation of respiratory pathogens, particularly methicillin-resistant Staphylococcus aureus, from bronchial aspirates of patients intubated on intensive care. Markers of elevated airway glucose are associated with similar patterns of respiratory infection in patients admitted with acute exacerbations of chronic obstructive pulmonary disease. Glucose at airway concentrations stimulates the growth of respiratory pathogens, over and above the effect of other nutrients. Elevated airway glucose concentrations may also worsen respiratory disease by promoting local inflammation. Hyperglycaemia may thus promote pulmonary infection, at least in part, by an effect on airway glucose concentrations. Therapeutic options, including systemic control of blood glucose and local manipulation of airway glucose homeostasis, will be considered.
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Affiliation(s)
- Emma H Baker
- Glucose and Pulmonary Infection Group, Cardiac and Vascular Sciences (Respiratory), St George's, University of London, Cranmer Terrace, London SW17 0RE, UK.
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29
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Everett-Grueter C, Edgerton DS, Donahue EP, Vaughan S, Chu CA, Sindelar DK, Cherrington AD. The effect of an acute elevation of NEFA concentrations on glucagon-stimulated hepatic glucose output. Am J Physiol Endocrinol Metab 2006; 291:E449-59. [PMID: 16608886 DOI: 10.1152/ajpendo.00043.2006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To determine the effect of nonesterified fatty acids (NEFA) on glucagon action, glucagon was infused intraportally (1.65 ng.min(-1).kg(-1)) for 3 h into 18-h-fasted, pancreatic-clamped conscious dogs in the presence [NEFA + glucagon (GGN)] or absence (GGN) of peripheral Intralipid plus heparin infusion. Additionally, hyperglycemic (HG), hyperglycemic-hyperlipidemic (NEFA + HG), and glycerol plus glucagon (GLYC + GGN) controls were studied. Arterial plasma glucagon concentrations rose equally in GGN, NEFA + GGN, and GLYC + GGN but remained basal in hyperglycemic controls. Peripheral infusions of Intralipid and heparin increased arterial plasma NEFA concentrations equally in NEFA + GGN and NEFA + HG and did not change in other protocols. After 15 min, glucagon infusion resulted in a rapid, brief increase in net hepatic glycogenolysis (NHGLY, mg.min(-1).kg(-1)) of approximately 6.0 in GGN and GLYC + GGN but only increased by 3.8 +/- 1.3 in NEFA + GGN. Thus increases in NHGLY, and consequently net hepatic glucose output (NHGO), were blunted by 40%, with no difference between the groups in the last 2.5 h of the study. NHGO and NHGLY did not significantly change in HG and NEFA + HG. Net hepatic gluconeogenic flux did not change in GGN, GLYC + GGN, or HG. However, Intralipid and heparin infusion resulted in similar increases in net hepatic gluconeogenic flux in NEFA + GGN and NEFA + HG. Thus elevated NEFA limit the initial increase in glucagon-stimulated HGO by blunting glycogenolysis, without having any effect on the gluconeogenic or glycogenolytic contributions or NHGO thereafter.
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Affiliation(s)
- Carrie Everett-Grueter
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA.
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30
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Jeoung N, Wu P, Joshi M, Jaskiewicz J, Bock C, Depaoli-Roach A, Harris R. Role of pyruvate dehydrogenase kinase isoenzyme 4 (PDHK4) in glucose homoeostasis during starvation. Biochem J 2006; 397:417-25. [PMID: 16606348 PMCID: PMC1533314 DOI: 10.1042/bj20060125] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The PDC (pyruvate dehydrogenase complex) is strongly inhibited by phosphorylation during starvation to conserve substrates for gluconeogenesis. The role of PDHK4 (pyruvate dehydrogenase kinase isoenzyme 4) in regulation of PDC by this mechanism was investigated with PDHK4-/- mice (homozygous PDHK4 knockout mice). Starvation lowers blood glucose more in mice lacking PDHK4 than in wild-type mice. The activity state of PDC (percentage dephosphorylated and active) is greater in kidney, gastrocnemius muscle, diaphragm and heart but not in the liver of starved PDHK4-/- mice. Intermediates of the gluconeogenic pathway are lower in concentration in the liver of starved PDHK4-/- mice, consistent with a lower rate of gluconeogenesis due to a substrate supply limitation. The concentration of gluconeogenic substrates is lower in the blood of starved PDHK4-/- mice, consistent with reduced formation in peripheral tissues. Isolated diaphragms from starved PDHK4-/- mice accumulate less lactate and pyruvate because of a faster rate of pyruvate oxidation and a reduced rate of glycolysis. BCAAs (branched chain amino acids) are higher in the blood in starved PDHK4-/- mice, consistent with lower blood alanine levels and the importance of BCAAs as a source of amino groups for alanine formation. Non-esterified fatty acids are also elevated more in the blood of starved PDHK4-/- mice, consistent with lower rates of fatty acid oxidation due to increased rates of glucose and pyruvate oxidation due to greater PDC activity. Up-regulation of PDHK4 in tissues other than the liver is clearly important during starvation for regulation of PDC activity and glucose homoeostasis.
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Affiliation(s)
- Nam Ho Jeoung
- *Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202-5122, U.S.A
| | - Pengfei Wu
- *Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202-5122, U.S.A
| | - Mandar A. Joshi
- *Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202-5122, U.S.A
| | - Jerzy Jaskiewicz
- *Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202-5122, U.S.A
| | - Cheryl B. Bock
- †Comprehensive Cancer Center, Duke University Medical Center, Durham, NC 27710, U.S.A
| | - Anna A. Depaoli-Roach
- *Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202-5122, U.S.A
| | - Robert A. Harris
- *Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202-5122, U.S.A
- To whom correspondence should be addressed, at Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Biotechnology Research and Training Center, 1345 W. 16th St., Indianapolis, IN 46202-2111, U.S.A. (email )
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Ernsberger P, Koletsky RJ. Metabolic effects of antihypertensive agents: role of sympathoadrenal and renin-angiotensin systems. Naunyn Schmiedebergs Arch Pharmacol 2006; 373:245-58. [PMID: 16783586 DOI: 10.1007/s00210-006-0080-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2006] [Accepted: 05/09/2006] [Indexed: 01/01/2023]
Abstract
Reports of beneficial, neutral and adverse impacts of antihypertensive drug classes on glucose and lipid metabolism can be found in human data. Furthermore, mechanisms for these diverse effects are often speculative and controversial. Clinical trial data on the metabolic effects of antihypertensive agents are highly contradictory. Comparisons of clinical trials involving different agents are complicated by differences in the spectrum of metabolic disturbances that accompany hypertension in different groups of patients. Two physiological systems are predominant at the interface between metabolic and cardiovascular regulation: the sympathetic nervous system (SNS) and the renin-angiotensin system (RAS). These two systems are major targets of antihypertensive drug actions, and also mediate many of the beneficial and adverse effects of antihypertensive agents on glucose and lipid metabolism. Thiazides and beta-adrenergic antagonists can adversely affect glucose and lipid metabolism, which are frequently compromised in human essential hypertension, and increase the incidence of new cases of diabetes. Laboratory studies confirm these effects, and suggest that compensatory activation of the SNS and RAS may be one mechanism. Other antihypertensives directly targeting the SNS and RAS may have beneficial effects on glucose and lipid metabolism, and may prevent diabetes. Resolution of the controversies surrounding the metabolic effects of antihypertensive agents can only be resolved by further laboratory studies, in addition to controlled clinical trials.
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Xie T, Plagge A, Gavrilova O, Pack S, Jou W, Lai EW, Frontera M, Kelsey G, Weinstein LS. The alternative stimulatory G protein alpha-subunit XLalphas is a critical regulator of energy and glucose metabolism and sympathetic nerve activity in adult mice. J Biol Chem 2006; 281:18989-99. [PMID: 16672216 PMCID: PMC1490322 DOI: 10.1074/jbc.m511752200] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The complex imprinted Gnas locus encodes several gene products including G(s)alpha, the ubiquitously expressed G protein alpha-subunit required for receptor-stimulated cAMP generation, and the neuroendocrine-specific G(s)alpha isoform XLalphas. XLalphas is only expressed from the paternal allele, whereas G(s)alpha is biallelically expressed in most tissues. XLalphas knock-out mice (Gnasxl(m+/p-)) have poor suckling and perinatal lethality, implicating XLalphas as critical for postnatal feeding. We have now examined the metabolic phenotype of adult Gnasxl(m+/p-) mice. Gnasxl(m+/p-) mice had reduced fat mass and lipid accumulation in adipose tissue, with increased food intake and metabolic rates. Gene expression profiling was consistent with increased lipid metabolism in adipose tissue. These changes likely result from increased sympathetic nervous system activity rather than adipose cell-autonomous effects, as we found that XLalphas is not normally expressed in adult adipose tissue, and Gnasxl(m+/p-) mice had increased urinary norepinephrine levels but not increased metabolic responsiveness to a beta3-adrenergic agonist. Gnasxl(m+/p-) mice were hypolipidemic and had increased glucose tolerance and insulin sensitivity. The similar metabolic profile observed in some prior paternal Gnas knock-out models results from XLalphas deficiency (or deficiency of the related alternative truncated protein XLN1). XLalphas (or XLN1) is a negative regulator of sympathetic nervous system activity in mice.
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Affiliation(s)
- Tao Xie
- From the Metabolic Diseases Branch and
| | - Antonius Plagge
- Laboratory of Developmental Genetics and Imprinting, The Babraham Institute, Cambridge, United Kingdom
| | - Oksana Gavrilova
- Mouse Metabolism Core Laboratory, National Institute of Diabetes, Digestive, and Kidney Diseases
| | - Stephanie Pack
- Mouse Metabolism Core Laboratory, National Institute of Diabetes, Digestive, and Kidney Diseases
| | - William Jou
- Mouse Metabolism Core Laboratory, National Institute of Diabetes, Digestive, and Kidney Diseases
| | - Edwin W. Lai
- Reproductive Biology and Medicine Branch, National Institute of Child Health and Human Development, and
- Clinical Neurocardiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Marga Frontera
- Laboratory of Developmental Genetics and Imprinting, The Babraham Institute, Cambridge, United Kingdom
| | - Gavin Kelsey
- Laboratory of Developmental Genetics and Imprinting, The Babraham Institute, Cambridge, United Kingdom
| | - Lee S. Weinstein
- From the Metabolic Diseases Branch and
- Address correspondence to: Lee S. Weinstein, Metabolic Diseases Branch, NIDDK/NIH, Bldg 10 Rm 8C101, Bethesda, Maryland 20892-1752 USA; Phone 301-402-2923; FAX 301-402-0374; E-mail:
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33
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Wong XW, Singh-Levett I, Hollingsworth LJ, Shaw GM, Hann CE, Lotz T, Lin J, Wong OSW, Chase JG. A novel, model-based insulin and nutrition delivery controller for glycemic regulation in critically ill patients. Diabetes Technol Ther 2006; 8:174-90. [PMID: 16734548 DOI: 10.1089/dia.2006.8.174] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Critically ill patients are often hyperglycemic and insulin resistant, as well as highly dynamic. Tight glucose control has been shown to significantly reduce mortality in critical care. A physiological model of the glucose-insulin regulatory system is improved and used to develop an adaptive control protocol utilizing both nutritional and insulin inputs to control hyperglycemia. The approach is clinically verified in a critical care patient cohort. METHODS A simple two-compartment model for glucose rate of appearance in plasma due to stepwise enteral glucose fluxes is developed and incorporated into a previously validated system model. A control protocol modulating intravenous insulin infusion and bolus, with an enteral feed rate, is developed, enabling tight and predictive glycemic regulation to preset targets. The control protocol is adaptive to patient time-variant effective insulin resistance. The model and protocol are verified in seven 10-h and one 24-h proof-of-concept clinical trials. Ethics approval was granted by the Canterbury Ethics Committee. RESULTS Insulin requirements varied widely following acute changes in patient physiology. The algorithm developed successfully adapted to patient metabolic status and insulin sensitivity, achieving an average target acquisition error of 9.3% with 90.7% of all targets achieved within +/-20%. Prediction errors may not be distinguishable from sensor measurement errors. Large errors (>20%) are attributable to highly dynamic and unpredictable changes in patient condition. CONCLUSIONS Tight, targeted stepwise regulation was exhibited in all trials. Overall, tight glycemic regulation is achieved in a broad critical care cohort with optimized insulin and nutrition delivery, effectively managing glycemia even with high effective insulin resistance.
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Affiliation(s)
- X W Wong
- Department of Mechanical Engineering, University of Canterbury, Dunedin, New Zealand
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34
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Gustavson SM, Rajotte RV, Hunkeler D, Lakey JRT, Edgerton DS, Neal DW, Snead WL, Penaloza AR, Cherrington AD. Islet auto-transplantation into an omental or splenic site results in a normal beta cell but abnormal alpha cell response to mild non-insulin-induced hypoglycemia. Am J Transplant 2005; 5:2368-77. [PMID: 16162184 DOI: 10.1111/j.1600-6143.2005.01041.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The present studies were designed to determine if totally pancreatectomized dogs that underwent islet auto-transplantation retained a functional pancreatic counterregulatory response to mild non-insulin-induced hypoglycemia. Six dogs underwent total pancreatectomy followed by islet auto-transplantation to spleen or omentum. The animals recovered and fasting plasma glucose and insulin levels were normal. Each study consisted of a 40-min control and 2-h test period. At the onset of the test period, a glycogen phosphorylase inhibitor was administered to create mild hypoglycemia. Plasma glucose in the transplanted dogs fell from 120 +/- 4 to 80 +/- 3 mg/dL, similar to the minimum in control dogs without islet auto-transplantation (108 +/- 2 to 84 +/- 5 mg/dL). The fall in plasma insulin was similar in both groups. Glucagon, however, rose in response to hypoglycemia in the control dogs (Delta24 +/- 7 pg/mL; p < 0.05), but failed to rise significantly in the transplanted dogs (Delta9 +/- 6 pg/mL). In fact, only 1 of 7 control dogs failed to increase plasma glucagon by at least 25%, whereas 4 of 6 transplanted dogs failed to do so. In conclusion, in conscious dogs with successfully auto-transplanted islets, the beta cell response to mild non-insulin-induced hypoglycemia was normal, whereas the alpha cell response was not.
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Affiliation(s)
- Stephanie M Gustavson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
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35
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Abstract
Infection leads to profound alterations in whole-body metabolism, which is characterized by marked acceleration of glucose, fat and protein, and amino acid flux. One of the complications of infection, especially in the nutritionally supported setting, is hyperglycemia. The hyperglycemia is caused by peripheral insulin resistance and alterations in hepatic glucose metabolism. The defects in hepatic glucose metabolism include overproduction of glucose and a failure of the liver to appropriately adapt when nutritional support is administered. Investigators have suggested that multiple factors contribute to the observed defects. In this review, I focus primarily on alterations in carbohydrate metabolism, examining both the metabolic response to infection and inflammatory stress, the role of the accompanying neuroendocrine and inflammatory responses in the metabolic response, and the interaction between the endocrine response to infection and nutritional support.
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Affiliation(s)
- Owen P McGuinness
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615, USA.
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36
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Aftab Guy D, Sandoval D, Richardson MA, Tate D, Davis SN. Effects of glycemic control on target organ responses to epinephrine in type 1 diabetes. Am J Physiol Endocrinol Metab 2005; 289:E258-65. [PMID: 15784645 DOI: 10.1152/ajpendo.00311.2004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Severe hypoglycemia occurs in intensively treated patients with type 1 diabetes mellitus (T1DM) due in part to deficient epinephrine counterregulatory responses. Previously, we have found that T1DM patients demonstrated a spectrum of altered responses to epinephrine at a variety of target organs compared with nondiabetic healthy subjects. What is not known is whether intensive glycemic control further modifies target organ responses in individuals with T1DM. Therefore, the aim of this study is to assess whether there is tissue specific (liver, muscle, adipose tissue, pancreas and cardiovascular) resistance to epinephrine in intensively controlled (IC) T1DM compared with those with conventional control (CC). Eight IC patients (age 33 +/- 4 yr, BMI 24 +/- 2 kg/m2, Hb A1C 6.7 +/- 0.1%), and 11 CC patients (age 35 +/- 3 yr, BMI 25 +/- 1 kg/m2, Hb A1C 9.6 +/- 0.1%) underwent two separate randomized, single-blind, 2-h hyperinsulinemic euglycemic clamp studies with (EPI) and without (NO EPI) epinephrine infusion. Epinephrine levels during EPI were similar in all groups (5,197 +/- 344 pmol/l). Glucose (5.3 +/- 0.1 mmol/l) and insulin levels (515 +/- 44 pmol/l) were similar in all groups during the glucose clamps. Endogenous glucose production (EGP) and glucose uptake (R(d)) were determined using [3-H3]glucose. Muscle biopsy was performed at the end of each study. IC had a significantly reduced EGP and R(d) responses to EPI compared with CC. Glucagon responses to EPI were similarly blunted in both IC and CC. Free fatty acid and glycerol response to EPI was greater in CC compared with IC. There was a significantly greater systolic blood pressure response to EPI in CC. We conclude that, despite similar epinephrine, insulin, and glucose levels, intensively treated T1DM patients had reduced cardiovascular, skeletal muscle, hepatic, and adipose target organ responses to EPI compared with conventionally treated T1DM patients.
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Affiliation(s)
- Deanna Aftab Guy
- 715 PRB, Div. of Diabetes, Endocrinology & Metabolism, Vanderbilt Univ. School of Medicine, Nashville, TN 37232-6303, USA
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Fagerholm V, Grönroos T, Marjamäki P, Viljanen T, Scheinin M, Haaparanta M. Altered glucose homeostasis in alpha2A-adrenoceptor knockout mice. Eur J Pharmacol 2005; 505:243-52. [PMID: 15556159 DOI: 10.1016/j.ejphar.2004.10.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 10/08/2004] [Accepted: 10/12/2004] [Indexed: 11/29/2022]
Abstract
To elucidate the functions of alpha2-adrenoceptor subtypes in metabolic regulation, we determined plasma glucose and insulin levels and tissue uptake of the glucose analogue 2-[18F]fluoro-2-deoxy-d-glucose ([18F]FDG) in C57Bl/6J wild-type (WT) and alpha2A-adrenoceptor knockout (alpha2A-KO) mice at baseline and following alpha2-adrenoceptor agonist ((+)-4-(S)-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole (dexmedetomidine)) and antagonist (4-[2-ethyl-2,3-dihydro-1H-inden-2-yl]-1H-imidazole (atipamezole)) administration. Basal glucose levels were 30% lower in alpha2A-KO mice than in WT mice. In WT mice, dexmedetomidine lowered insulin and elevated glucose levels, and atipamezole reduced glucose levels. In alpha2A-KO mice, neither drug affected the glucose or insulin levels. [18F]FDG uptake was investigated in plasma, heart, liver, kidney, pancreas, lung, fat, and skeletal muscle. Cardiac [18F]FDG uptake was a sensitive indicator of sympathetic function. Liver [18F]FDG uptake conformed to the plasma glucose levels. In alpha2A-KO mice, drug effects on [18F]FDG tissue uptake were absent. Thus, the alpha2A-adrenoceptor is the alpha2-adrenoceptor subtype primarily involved in the regulation of blood glucose homeostasis in vivo.
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Affiliation(s)
- Veronica Fagerholm
- Department of Pharmacology and Clinical Pharmacology, University of Turku, Itäinen Pitkäkatu 4B, FI-20520 Turku, Finland
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Moore MC, DiCostanzo CA, Dardevet D, Lautz M, Farmer B, Neal DW, Cherrington AD. Portal infusion of a selective serotonin reuptake inhibitor enhances hepatic glucose disposal in conscious dogs. Am J Physiol Endocrinol Metab 2004; 287:E1057-63. [PMID: 15315909 DOI: 10.1152/ajpendo.00313.2004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Intraportal delivery of serotonin enhanced net hepatic glucose uptake (NHGU) during a hyperinsulinemic hyperglycemic clamp, but serotonin elevated catecholamines and can cause gastrointestinal distress. We hypothesized that the selective serotonin reuptake inhibitor (SSRI) fluvoxamine would enhance NHGU without side effects. Arteriovenous difference and tracer ([3-(3)H]glucose) techniques were used in conscious 42-h-fasted dogs. Experiments consisted of equilibration (-120 to -30 min), basal (-30 to 0 min), and experimental (EXP; 0-270 min) periods. During EXP, somatostatin, fourfold basal intraportal insulin, basal intraportal glucagon, and peripheral glucose (to double the hepatic glucose load) were infused. Saline (SAL) was infused intraportally during 0-90 min (P1), and fluvoxamine was infused intraportally at 0.5, 1, and 2 mug.kg(-1).min(-1) from 90 to 150 (P2), 150 to 210 (P3), and 210 to 270 (P4) min, respectively, in the FLUV group (n = 8). The SAL group (n = 9) received intraportal saline during 0-270 min. NHGU in SAL was 13.9 +/- 1.7 and 17.0 +/- 2.0 mumol.kg(-1).min(-1) in P3-P4, respectively, while NHGU in FLUV averaged 19.7 +/- 2.8 and 26.6 +/- 3.0 mumol.kg(-1).min(-1) (P < 0.05 vs. SAL). Net hepatic carbon retention was greater (P < 0.05) in FLUV than in SAL (17.6 +/- 2.6 vs. 13.9 +/- 2.7 and 23.8 +/- 3.0 vs. 14.4 +/- 3.3 mumol.kg(-1).min(-1) in P3-P4, respectively), and final hepatic glycogen concentrations were 50% greater in FLUV (P < 0.005). Nonhepatic glucose uptake was greater in SAL than in FLUV at 270 min (P < 0.05). Catecholamine concentrations remained basal, and the animals evidenced no distress. Thus fluvoxamine enhanced NHGU and hepatic carbon storage without raising circulating serotonin concentrations or causing stress, suggesting that hepatic-targeted SSRIs might be effective in reducing postprandial hyperglycemia in individuals with diabetes or impaired glucose tolerance.
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Affiliation(s)
- Mary Courtney Moore
- Dept. of Molecular Physiology & Biophysics, 702 Light Hall, Vanderbilt University School of Medicine, Nashville, TN 37232-0615, USA.
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Gustavson SM, Chu CA, Nishizawa M, Neal D, Farmer B, Yang Y, Donahue EP, Flakoll P, Cherrington AD. Effects of hyperglycemia, glucagon, and epinephrine on renal glucose release in the conscious dog. Metabolism 2004; 53:933-41. [PMID: 15254890 DOI: 10.1016/j.metabol.2004.01.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The role of renal glucose production after an overnight fast and in response to different hormonal conditions has been debated. The aim of this study was to determine whether hyperglycemia, glucagon, or epinephrine can affect renal glucose production. In 18-hour fasted conscious dogs a pancreatic clamp initially fixed insulin and glucagon at basal levels, following which 1 of 4 protocols was instituted. In G+E glucagon (1.5 ng. kg(-1). min(-1); portally) and epinephrine (50 ng. kg(-1). min(-1); peripherally) were increased, in G glucagon was increased alone, in E epinephrine was increased alone, and in C neither were increased. In G, E, and C, glucose was infused to match the hyperglycemia in G+E (approximately 250 mg/dL). The average net renal glucose output during the last 2 hours was not different from the basal values in any group. Furthermore, the changes in unidirectional renal glucose production were not significantly different among groups. Therefore, after an overnight fast in the conscious dog, the kidneys do not significantly contribute to overall glucose production or respond to glucagon or epinephrine.
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Affiliation(s)
- Stephanie M Gustavson
- Department of Molecular Physiology and Biophysics and Diabetes Research and Training Center, Vanderbilt University, Nashville, TN, USA
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Uyama N, Geerts A, Reynaert H. Neural connections between the hypothalamus and the liver. ACTA ACUST UNITED AC 2004; 280:808-20. [PMID: 15382020 DOI: 10.1002/ar.a.20086] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
After receiving information from afferent nerves, the hypothalamus sends signals to peripheral organs, including the liver, to keep homeostasis. There are two ways for the hypothalamus to signal to the peripheral organs: by stimulating the autonomic nerves and by releasing hormones from the pituitary gland. In order to reveal the involvement of the autonomic nervous system in liver function, we focus in this study on autonomic nerves and neuroendocrine connections between the hypothalamus and the liver. The hypothalamus consists of three major areas: lateral, medial, and periventricular. Each area has some nuclei. There are two important nuclei and one area in the hypothalamus that send out the neural autonomic information to the peripheral organs: the ventromedial hypothalamic nucleus (VMH) in the medial area, the lateral hypothalamic area (LHA), and the periventricular hypothalamic nucleus (PVN) in the periventricular area. VMH sends sympathetic signals to the liver via the celiac ganglia, the LHA sends parasympathetic signals to the liver via the vagal nerve, and the PVN integrates information from other areas of the hypothalamus and sends both autonomic signals to the liver. As for the afferent nerves, there are two pathways: a vagal afferent and a dorsal afferent nerve pathway. Vagal afferent nerves are thought to play a role as sensors in the peripheral organs and to send signals to the brain, including the hypothalamus, via nodosa ganglia of the vagal nerve. On the other hand, dorsal afferent nerves are primary sensory nerves that send signals to the brain via lower thoracic dorsal root ganglia. In the liver, many nerves contain classical neurotransmitters (noradrenaline and acetylcholine) and neuropeptides (substance P, calcitonin gene-related peptide, neuropeptide Y, vasoactive intestinal polypeptide, somatostatin, glucagon, glucagon-like peptide, neurotensin, serotonin, and galanin). Their distribution in the liver is species-dependent. Some of these nerves are thought to be involved in the regulation of hepatic function as well as of hemodynamics. In addition to direct neural connections, the hypothalamus can affect metabolic functions by neuroendocrine connections: the hypothalamus-pancreas axis, the hypothalamus-adrenal axis, and the hypothalamus-pituitary axis. In the hypothalamus-pancreas axis, autonomic nerves release glucagon and insulin, which directly enter the liver and affect liver metabolism. In the hypothalamus-adrenal axis, autonomic nerves release catecholamines such as adrenaline and noradrenaline from the adrenal medulla, which also affects liver metabolism. In the hypothalamus-pituitary axis, release of glucocorticoids and thyroid hormones is stimulated by pituitary hormones. Both groups of hormones modulate hepatic metabolism. Taken together, the hypothalamus controls liver functions by neural and neuroendocrine connections.
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Affiliation(s)
- Naoki Uyama
- Laboratory for Molecular Liver Cell Biology, Vrije Universiteit Brussel, Belgium.
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41
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de Galan BE, Rietjens SJ, Tack CJ, van der Werf SP, Sweep CGJ, Lenders JWM, Smits P. Antecedent adrenaline attenuates the responsiveness to but not the release of counterregulatory hormones during subsequent hypoglycemia. J Clin Endocrinol Metab 2003; 88:5462-7. [PMID: 14602790 DOI: 10.1210/jc.2003-030407] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Hypoglycemia unawareness is thought to be the consequence of recurrent hypoglycemia, yet the underlying mechanism is still incompletely understood. The aim of the present study was to determine the role of antecedent elevated adrenaline in the pathogenesis of hypoglycemia unawareness. Sixteen healthy volunteers (eight of either sex) participated in two experiments, performed in random order and at least 3 wk apart. During the morning, three consecutive doses of 0.04, 0.06, and 0.08 microg.kg(-1).min(-1) of adrenaline or matching placebo (normal saline) were infused for the total duration of 1 h. Three hours later, a hyperinsulinemic (360 pmol.m(-2).min(-1)) two-step hypoglycemic (5.0-3.5-2.5 mmol.liter(-1)) clamp study was performed. During hypoglycemia, hypoglycemic symptoms, counterregulatory hormones, cardiovascular responses, and cognitive function were monitored. Hypoglycemia induced similar responses of autonomic and neuroglycopenic symptoms, counterregulatory hormones, and lengthening in reaction time on the choice reaction time task, irrespective of antecedent infusions. However, prior adrenaline was associated with higher exogenous glucose requirements at hypoglycemic nadir (10.1 +/- 1.3 vs. 7.3 +/- 1.3 micromol.kg(-1).min(-1), P = 0.017), an attenuated hypoglycemia-induced fall in blood pressure (mean arterial pressure, -13 +/- 2 vs. -8 +/- 2 mm Hg, P = 0.006), and preserved cognitive function as assessed by the symbol digit test during hypoglycemia, when compared with prior placebo. We conclude that elevated adrenaline attenuates the responsiveness to, but not the release of counterregulatory hormones during subsequent hypoglycemia. As such, adrenaline's role in the development of hypoglycemia unawareness is limited.
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Affiliation(s)
- Bastiaan E de Galan
- Department of Medicine, University Medical Center Nijmegen, Nijmegen 6500HB, The Netherlands
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42
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Gustavson SM, Nishizawa M, Farmer B, Neal D, Brissova M, Powers AC, Cherrington AD. A fall in portal vein insulin does not cause the alpha-cell response to mild, non-insulin-induced hypoglycemia in conscious dogs. Metabolism 2003; 52:1418-25. [PMID: 14624400 DOI: 10.1016/s0026-0495(03)00321-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The aim of the present study was to determine whether a decrease in the portal vein insulin level during non-insulin-induced hypoglycemia is sensed and is responsible for the normal increase in glucagon release from the alpha cell. To address this aim, a glycogen phosphorylase inhibitor was used to create mild, non-insulin-induced hypoglycemia in 2 groups of 18-hour fasted conscious dogs. Arterial insulin was clamped at a basal level in both groups, but in one group (PE) the portal vein insulin level was permitted to fall by approximately 65% while in the other group (POR) it was clamped at a basal level. In both groups glucose was infused at a variable rate to clamp the plasma glucose level at approximately 70 mg/dL. Plasma glucagon (pg/mL) rose to indistinguishable maxima in both groups (56 +/- 3 in PE and 67 +/- 9 in POR). Likewise, glucagon secretion (pg/kg/min) increased similarly (189 +/- 32 to 455 +/- 203 in PE and 192 +/- 50 to 686 +/- 237 in POR). Thus, the increase in glucagon release was not inhibited when the portal vein insulin level was prevented from decreasing (POR group). Clearly, a fall in the portal vein insulin level is not required for a normal alpha-cell response to mild, non-insulin-induced hypoglycemia.
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Affiliation(s)
- Stephanie M Gustavson
- Department of Molecular Physiology, Diabetes Research and Training Center, Vanderbilt University Medical Center, Nashville, TN 37232-6303, USA
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43
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Meyer C, Stumvoll M, Welle S, Woerle HJ, Haymond M, Gerich J. Relative importance of liver, kidney, and substrates in epinephrine-induced increased gluconeogenesis in humans. Am J Physiol Endocrinol Metab 2003; 285:E819-26. [PMID: 12959936 DOI: 10.1152/ajpendo.00145.2003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Splanchnic and renal net balance measurements indicate that lactate and glycerol may be important precursors for epinephrine-stimulated gluconeogenesis (GNG) in liver and kidney, but the effects of epinephrine on their renal and hepatic conversion to glucose in humans have not yet been reported. We therefore used a combination of renal balance and isotopic techniques in nine postabsorptive volunteers to measure systemic and renal GNG from these precursors before and during a 3-h infusion of epinephrine (270 pmol. kg-1. min-1) and calculated hepatic GNG as the difference between systemic and renal rates. During infusion of epinephrine, renal and hepatic GNG from lactate increased 4- to 6-fold and accounted for approximately 85 and 70% of renal and hepatic glucose release, respectively, at the end of study; renal and hepatic GNG from glycerol increased approximately 1.5- to 2-fold and accounted for approximately 7-9% of renal and hepatic glucose release at the end of study. The increased renal GNG from lactate and glycerol was due not only to their increased renal uptake (approximately 3.3- and 1.4-fold, respectively) but also increased renal gluconeogenic efficiency (approximately 1.8- and 1.5-fold). The increased renal uptake of lactate and glycerol was wholly due to their increased arterial concentrations, since their renal fractional extraction remained unchanged and renal blood flow decreased. We conclude that 1) lactate is the predominant precursor for epinephrine-stimulated GNG in both liver and kidney, 2) hepatic and renal GNG from lactate and glycerol are similarly sensitive to stimulation by epinephrine, and 3) epinephrine increases renal GNG from lactate and glycerol by increasing substrate availability and the gluconeogenic efficiency of the kidney.
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Affiliation(s)
- Christian Meyer
- Department of Medicine, University of Roichester School of Medicine, Rochester, NY 14642, USA.
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Moore MC, Cherrington AD, Wasserman DH. Regulation of hepatic and peripheral glucose disposal. Best Pract Res Clin Endocrinol Metab 2003; 17:343-64. [PMID: 12962690 DOI: 10.1016/s1521-690x(03)00036-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Precise regulation of hepatic and peripheral glucose uptake is essential to preserve glucose homeostasis. The liver extracts approximately 1/3 of an oral glucose load, skeletal muscle extracts approximately 1/3, and other tissues, particularly the central nervous system and the formed elements of the blood, take up the balance. The load of glucose reaching the liver, the insulin concentration, and the route of glucose delivery (the hepatic portal or a peripheral vein) are key determinants of the rate of net hepatic glucose uptake. Glucose uptake by muscle requires three steps: delivery of glucose from the blood to the muscle, transport of glucose across the muscle membrane, and phosphorylation of glucose, processes affected by glycaemia and insulinaemia. Exercise stimulates insulin-dependent and -independent muscle glucose uptake, as well as the liver's ability to take up glucose.
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Affiliation(s)
- Mary Courtney Moore
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 702 Light Hall, Nashville, TN 37232-0615, USA
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45
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Gustavson SM, Chu CA, Nishizawa M, Farmer B, Neal D, Yang Y, Vaughan S, Donahue EP, Flakoll P, Cherrington AD. Glucagon's actions are modified by the combination of epinephrine and gluconeogenic precursor infusion. Am J Physiol Endocrinol Metab 2003; 285:E534-44. [PMID: 12736160 DOI: 10.1152/ajpendo.00059.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
It was previously shown that glucagon and epinephrine have additive effects on both gluconeogenic and glycogenolytic flux. However, the changes in gluconeogenic substrates may have been limiting and thus may have prevented a synergistic effect on gluconeogenesis and a reciprocal inhibitory effect on glycogenolysis. Thus the aim of the present study was to determine if glucagon has a greater gluconeogenic and a smaller glycogenolytic effect in the presence of both epinephrine and clamped gluconeogenic precursors. Two groups (Epi and G + Epi + P) of 18-h-fasted conscious dogs were studied. In Epi, epinephrine was increased, and in G + Epi + P, glucagon and epinephrine were increased. Gluconeogenic precursors (lactate and alanine) were infused in G + Epi + P to match the rise that occurred in Epi. Insulin and glucose levels were also controlled and were similar in the two groups. Epinephrine and precursor administration increased glucagon's effect on gluconeogenesis (4.5-fold; P < 0.05) and decreased glucagon's effect on glycogenolysis (85%; P = 0.08). Thus, in the presence of both hormones, and when the gluconeogenic precursor supply is maintained, gluconeogenic flux is potentiated and glycogenolytic flux is inhibited.
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Affiliation(s)
- Stephanie M Gustavson
- Department of Molecular Physiology, Vanderbilt University Medical Center, Nashville, TN 37232-6303, USA.
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46
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Courtney CH, Atkinson AB, Ennis CN, Sheridan B, Bell PM. Comparison of the priming effects of pulsatile and continuous insulin delivery on insulin action in man. Metabolism 2003; 52:1050-5. [PMID: 12898472 DOI: 10.1016/s0026-0495(03)00156-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulin is normally secreted in man in regular pulses every 5 to 15 minutes. Disordered pulsation has been demonstrated in several insulin-resistant states and it is unclear whether this represents a primary beta-cell defect contributing to impairment of peripheral insulin action or rather is a consequence of insulin resistance. Basal or near basal insulin administration by pulsatile infusion augments hypoglycemic effect and improves insulin-mediated glucose uptake compared with insulin by continuous infusion. To date no study has examined whether normal basal insulin pulsatility is required to preserve subsequent insulin sensitivity during hyperinsulinemia. We studied the effect of overnight pulsatile versus continuous basal insulin on a subsequent hyperinsulinemic euglycemic clamp. Nineteen normal volunteers (male:female ratio, 17:2; mean age +/- SEM, 26.1 +/- 2.3 years) were studied on 2 occasions each. Endogenous insulin secretion was inhibited by octreotide (0.43 microg kg(-1). h(-1)) and replaced overnight at 5.4 mU kg(-1). h(-1) either by continuous infusion or in 2-minute pulses every 13 minutes (n = 10) or every 7 minutes (n = 9). Glucagon was replaced at physiological concentration by continuous infusion (30 ng. kg(-1). h(-1)). Venous plasma glucose overnight was not significantly different between the pulsatile and continuous protocols. After discontinuing the overnight insulin infusion, insulin action was assessed during a hyperinsulinemic euglycemic clamp (1 mU kg(-1). h(-1)). Glucose infusion rates at steady-state during the hyperinsulinemic clamp were similar between continuous and both frequencies of pulsatile infusion (continuous 44.6 +/- 4.3 micromol. kg(-1). min(-1) v 13-minute pulsatile 41.7 +/- 5.9 micromol. kg(-1). min(-1), P =.27; continuous 34.6 +/- 2.5 micromol. kg(-1) min(-1) v 7-minute pulsatile 41.4 +/- 3.2 micromol. kg(-1). min(-1), P =.08). We conclude that overnight pulsatile compared with continuous insulin administration has no different effect on subsequent peripheral insulin-mediated glucose uptake. A priming effect cannot therefore explain the previously demonstrated association between endogenous insulin pulse frequency and peripheral insulin action.
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Affiliation(s)
- C H Courtney
- Regional Centre for Endocrinology and Diabetes, Royal Victoria Hospital, Belfast, UK
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Nishizawa M, Moore MC, Shiota M, Gustavson SM, Snead WL, Neal DW, Cherrington AD. Effect of intraportal glucagon-like peptide-1 on glucose metabolism in conscious dogs. Am J Physiol Endocrinol Metab 2003; 284:E1027-36. [PMID: 12569088 DOI: 10.1152/ajpendo.00503.2002] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Arteriovenous difference and tracer ([3-(3)H]glucose) techniques were used in 42-h-fasted conscious dogs to identify any insulin-like effects of intraportally administered glucagon-like peptide 1-(7-36)amide (GLP-1). Each study consisted of an equilibration, a basal, and three 90-min test periods (P1, P2, and P3) during which somatostatin, intraportal insulin (3-fold basal) and glucagon (basal), and peripheral glucose were infused. Saline was infused intraportally in P1. During P2 and P3, GLP-1 was infused intraportally at 0.9 and 5.1 pmol. kg(-1). min(-1) in eight dogs, at 10 and 20 pmol. kg(-1). min(-1) in seven dogs, and at 0 pmol. kg(-1). min(-1) in eight dogs (control group). Net hepatic glucose uptake was significantly enhanced during GLP-1 infusion at 20 pmol. kg(-1). min(-1) [21.8 vs. 13.4 micromol. kg(-1). min(-1) (control), P < 0.05]. Glucose utilization was significantly increased during infusion at 10 and 20 pmol. kg(-1). min(-1) [87.3 +/- 8.3 and 105.3 +/- 12.8, respectively, vs. 62.2 +/- 5.3 and 74.7 +/- 7.4 micromol. kg(-1). min(-1) (control), P < 0.05]. The glucose infusion rate required to maintain hyperglycemia was increased (P < 0.05) during infusion of GLP-1 at 5.1, 10, and 20 pmol. kg(-1). min(-1) (22, 36, and 32%, respectively, greater than control). Nonhepatic glucose uptake increased significantly during delivery of GLP-1 at 5.1 and 10 pmol. kg(-1). min(-1) (25 and 46% greater than control) and tended (P = 0.1) to increase during GLP-1 infusion at 20 pmol. kg(-1). min(-1) (24% greater than control). Intraportal infusion of GLP-1 at high physiological and pharmacological rates increased glucose disposal primarily in nonhepatic tissues.
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Affiliation(s)
- Makoto Nishizawa
- Department of Molecular Physiology & Biophysics, Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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Gustavson SM, Chu CA, Nishizawa M, Farmer B, Neal D, Yang Y, Donahue EP, Flakoll P, Cherrington AD. Interaction of glucagon and epinephrine in the control of hepatic glucose production in the conscious dog. Am J Physiol Endocrinol Metab 2003; 284:E695-707. [PMID: 12626324 DOI: 10.1152/ajpendo.00308.2002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Epinephrine increases net hepatic glucose output (NHGO) mainly via increased gluconeogenesis, whereas glucagon increases NHGO mainly via increased glycogenolysis. The aim of the present study was to determine how the two hormones interact in controlling glucose production. In 18-h-fasted conscious dogs, a pancreatic clamp initially fixed insulin and glucagon at basal levels, following which one of four protocols was instituted. In G + E, glucagon (1.5 ng x kg(-1) x min(-1); portally) and epinephrine (50 ng x kg(-1) x min(-1); peripherally) were increased; in G, glucagon was increased alone; in E, epinephrine was increased alone; and in C, neither was increased. In G, E, and C, glucose was infused to match the hyperglycemia seen in G + E ( approximately 250 mg/dl). The areas under the curve for the increase in NHGO, after the change in C was subtracted, were as follows: G = 661 +/- 185, E = 424 +/- 158, G + E = 1178 +/- 57 mg/kg. Therefore, the overall effects of the two hormones on NHGO were additive. Additionally, glucagon exerted its full glycogenolytic effect, whereas epinephrine exerted its full gluconeogenic effect, such that both processes increased significantly during concurrent hormone administration.
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Affiliation(s)
- Stephanie M Gustavson
- Department of Molecular Physiology and Biophysics,Vanderbilt University, Nashville, Tennessee 37232, USA.
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Chu CA, Galassetti P, Igawa K, Sindelar DK, Neal DW, Burish M, Cherrington AD. Interaction of free fatty acids and epinephrine in regulating hepatic glucose production in conscious dogs. Am J Physiol Endocrinol Metab 2003; 284:E291-301. [PMID: 12531743 DOI: 10.1152/ajpendo.00565.2001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
To determine the effects of an increase in lipolysis on the glycogenolytic effect of epinephrine (EPI), the catecholamine was infused portally into 18-h-fasted conscious dogs maintained on a pancreatic clamp in the presence [portal (Po)-EPI+FFA, n = 6] and absence (Po-EPI+SAL, n = 6) of peripheral Intralipid infusion. Control groups with high glucose (70% increase) and free fatty acid (FFA; 200% increase; HG+FFA, n = 6) and high glucose alone (HG+SAL, n = 6) were also included. Hepatic sinusoidal EPI levels were elevated (Delta 568 +/- 77 and Delta 527 +/- 37 pg/ml, respectively) in Po-EPI+SAL and EPI+FFA but remained basal in HG+FFA and HG+SAL. Arterial plasma FFA increased from 613 +/- 73 to 1,633 +/- 101 and 746 +/- 112 to 1,898 +/- 237 micromol/l in Po-EPI+FFA and HG+FFA but did not change in EPI+SAL or HG+SAL. Net hepatic glycogenolysis increased from 1.5 +/- 0.3 to 3.1 +/- 0.4 mg x kg(-1) x min(-1) (P < 0.05) by 30 min in response to portal EPI but did not rise (1.8 +/- 0.2 to 2.1 +/- 0.3 mg x kg(-1) x min(-1)) in response to Po-EPI+FFA. Net hepatic glycogenolysis decreased from 1.7 +/- 0.2 to 0.9 +/- 0.2 and 1.6 +/- 0.2 to 0.7 +/- 0.2 mg x kg(-1) x min(-1) by 30 min in HG+FFA and HG+SAL. Hepatic gluconeogenic flux to glucose 6-phosphate increased from 0.6 +/- 0.1 to 1.2 +/- 0.1 mg x kg(-1) x min(-1) (P < 0.05; by 3 h) and 0.7 +/- 0.1 to 1.6 +/- 0.1 mg x kg(-1) x min(-1) (P < 0.05; at 90 min) in HG+FFA and Po-EPI+FFA. The gluconeogenic parameters remained unchanged in the Po-EPI+SAL and HG+SAL groups. In conclusion, increased FFA markedly changed the mechanism by which EPI stimulated hepatic glucose production, suggesting that its overall lipolytic effect may be important in determining its effect on the liver.
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Affiliation(s)
- Chang An Chu
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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50
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Coker RH, Koyama Y, Denny JC, Camacho RC, Lacy DB, Wasserman DH. Prevention of overt hypoglycemia during exercise: stimulation of endogenous glucose production independent of hepatic catecholamine action and changes in pancreatic hormone concentration. Diabetes 2002; 51:1310-8. [PMID: 11978626 DOI: 10.2337/diabetes.51.5.1310] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
These studies were conducted to determine the magnitude and mechanism of compensation for impaired glucagon and insulin responses to exercise. For this purpose, dogs underwent surgery >16 days before experiments, at which time flow probes were implanted and silastic catheters were inserted. During experiments, glucagon and insulin were fixed at basal levels during rest and exercise using a pancreatic clamp with glucose clamped (PC/GC; n = 5), a pancreatic clamp with glucose unclamped (PC; n = 7), or a pancreatic clamp with glucose unclamped + intraportal propranolol and phentolamine hepatic alpha- and beta-adrenergic receptor blockade (PC/HAB; n = 6). Glucose production (R(a)) was measured isotopically. Plasma glucose was constant in PC/GC, but fell from basal to exercise in PC and PC/HAB. R(a) was unchanged with exercise in PC/GC, but was slightly increased during exercise in PC and PC/HAB. Despite minimal increases in epinephrine in PC/GC, epinephrine increased approximately sixfold in PC and PC/HAB during exercise. In summary, during moderate exercise, 1) the increase in R(a) is absent in PC/GC; 2) only a moderate fall in arterial glucose occurs in PC, due to a compensatory increase in R(a); and 3) the increase in R(a) is preserved in PC/HAB. In conclusion, stimulation of R(a) by a mechanism independent of pancreatic hormones and hepatic adrenergic stimulation is a primary defense against overt hypoglycemia.
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Affiliation(s)
- Robert H Coker
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
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