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Hoffman EG, D’Souza NC, Liggins RT, Riddell MC. Pharmacologic inhibition of somatostatin receptor 2 to restore glucagon counterregulation in diabetes. Front Pharmacol 2024; 14:1295639. [PMID: 38298268 PMCID: PMC10829877 DOI: 10.3389/fphar.2023.1295639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 12/13/2023] [Indexed: 02/02/2024] Open
Abstract
Glucose homeostasis is primarily maintained by pancreatic hormones, insulin and glucagon, with an emerging role for a third islet hormone, somatostatin, in regulating insulin and glucagon responses. Under healthy conditions, somatostatin secreted from pancreatic islet δ-cells inhibits both insulin and glucagon release through somatostatin receptor- induced cAMP-mediated downregulation and paracrine inhibition of β- and α-cells, respectively. Since glucagon is the body's most important anti-hypoglycemic hormone, and because glucagon counterregulation to hypoglycemia is lost in diabetes, the study of somatostatin biology has led to new investigational medications now in development that may help to restore glucagon counterregulation in type 1 diabetes. This review highlights the normal regulatory role of pancreatic somatostatin signaling in healthy islet function and how the inhibition of somatostatin receptor signaling in pancreatic α-cells may restore normal glucagon counterregulation in diabetes mellitus.
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Affiliation(s)
- Emily G. Hoffman
- School of Kinesiology and Health Science, Muscle Health Research Centre, York University, Toronto, ON, Canada
| | - Ninoschka C. D’Souza
- School of Kinesiology and Health Science, Muscle Health Research Centre, York University, Toronto, ON, Canada
| | | | - Michael C. Riddell
- School of Kinesiology and Health Science, Muscle Health Research Centre, York University, Toronto, ON, Canada
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2
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Tripyla A, Herzig D, Reverter-Branchat G, Pavan J, Schiavon M, Eugster PJ, Grouzmann E, Nakas CT, Sauvinet V, Meiller L, Zehetner J, Giachino D, Nett P, Gawinecka J, Del Favero S, Thomas A, Thevis M, Dalla Man C, Bally L. Counter-regulatory responses to postprandial hypoglycaemia in patients with post-bariatric hypoglycaemia vs surgical and non-surgical control individuals. Diabetologia 2023; 66:741-753. [PMID: 36648553 PMCID: PMC9947092 DOI: 10.1007/s00125-022-05861-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 11/21/2022] [Indexed: 01/18/2023]
Abstract
AIMS/HYPOTHESIS Post-bariatric hypoglycaemia is an increasingly recognised complication of bariatric surgery, manifesting particularly after Roux-en-Y gastric bypass. While hyperinsulinaemia is an established pathophysiological feature, the role of counter-regulation remains unclear. We aimed to assess counter-regulatory hormones and glucose fluxes during insulin-induced postprandial hypoglycaemia in patients with post-bariatric hypoglycaemia after Roux-en-Y gastric bypass vs surgical and non-surgical control individuals. METHODS In this case-control study, 32 adults belonging to four groups with comparable age, sex and BMI (patients with post-bariatric hypoglycaemia, Roux-en-Y gastric bypass, sleeve gastrectomy and non-surgical control individuals) underwent a postprandial hypoglycaemic clamp in our clinical research unit to reach the glycaemic target of 2.5 mmol/l 150-170 min after ingesting 15 g of glucose. Glucose fluxes were assessed during the postprandial and hypoglycaemic period using a dual-tracer approach. The primary outcome was the incremental AUC of glucagon during hypoglycaemia. Catecholamines, cortisol, growth hormone, pancreatic polypeptide and endogenous glucose production were also analysed during hypoglycaemia. RESULTS The rate of glucose appearance after oral administration, as well as the rates of total glucose appearance and glucose disappearance, were higher in both Roux-en-Y gastric bypass groups vs the non-surgical control group in the early postprandial period (all p<0.05). During hypoglycaemia, glucagon exposure was significantly lower in all surgical groups vs the non-surgical control group (all p<0.01). Pancreatic polypeptide levels were significantly lower in patients with post-bariatric hypoglycaemia vs the non-surgical control group (median [IQR]: 24.7 [10.9, 38.7] pmol/l vs 238.7 [186.3, 288.9] pmol/l) (p=0.005). Other hormonal responses to hypoglycaemia and endogenous glucose production did not significantly differ between the groups. CONCLUSIONS/INTERPRETATION The glucagon response to insulin-induced postprandial hypoglycaemia is lower in post-bariatric surgery individuals compared with non-surgical control individuals, irrespective of the surgical modality. No significant differences were found between patients with post-bariatric hypoglycaemia and surgical control individuals, suggesting that impaired counter-regulation is not a root cause of post-bariatric hypoglycaemia. TRIAL REGISTRATION ClinicalTrials.gov NCT04334161.
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Affiliation(s)
- Afroditi Tripyla
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - David Herzig
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Gemma Reverter-Branchat
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Jacopo Pavan
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Michele Schiavon
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Philippe J Eugster
- Laboratory of Catecholamines and Peptides, Service of Clinical Pharmacology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Eric Grouzmann
- Laboratory of Catecholamines and Peptides, Service of Clinical Pharmacology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Christos T Nakas
- School of Agricultural Sciences, Laboratory of Biometry, University of Thessaly, Volos, Greece
- University Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Valérie Sauvinet
- Centre de Recherche Nutrition Humaine Rhône-Alpes, Univ-Lyon, Inserm, INRAe, Claude Bernard Lyon1 University, Hospices Civils de Lyon, Centre Hospitalier Lyon Sud, Pierre Bénite, France
| | - Laure Meiller
- Centre de Recherche Nutrition Humaine Rhône-Alpes, Univ-Lyon, Inserm, INRAe, Claude Bernard Lyon1 University, Hospices Civils de Lyon, Centre Hospitalier Lyon Sud, Pierre Bénite, France
| | - Joerg Zehetner
- Department of Visceral Surgery, Hirslanden Clinic Beau-Site, Bern, Switzerland
| | - Daniel Giachino
- Department of Visceral Surgery, Lindenhofspital, Bern, Switzerland
| | - Philipp Nett
- Department of Visceral Surgery and Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Joanna Gawinecka
- Institute of Clinical Chemistry, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Simone Del Favero
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Andreas Thomas
- Institute of Biochemistry / Center for Preventive Doping Research, German Sport University Cologne, Cologne, Germany
| | - Mario Thevis
- Institute of Biochemistry / Center for Preventive Doping Research, German Sport University Cologne, Cologne, Germany
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Lia Bally
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
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3
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Orfanos S, Toygar T, Berthold-Losleben M, Chechko N, Durst A, Laoutidis ZG, Vocke S, Weidenfeld C, Schneider F, Karges W, Beckmann CF, Habel U, Kohn N. Investigating the impact of overnight fasting on intrinsic functional connectivity: a double-blind fMRI study. Brain Imaging Behav 2019; 12:1150-1159. [PMID: 29071464 PMCID: PMC6063348 DOI: 10.1007/s11682-017-9777-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The human brain depends mainly on glucose supply from circulating blood as an energy substrate for its metabolism. Most of the energy produced by glucose catabolism in the brain is used to support intrinsic communication purposes in the absence of goal-directed activity. This intrinsic brain function can be detected with fMRI as synchronized fluctuations of the BOLD signal forming functional networks. Here, we report results from a double-blind, placebo controlled, cross-over study addressing changes in intrinsic brain activity in the context of very low, yet physiological, blood glucose levels after overnight fasting. Comparison of four major resting state networks in a fasting state and a state of elevated blood glucose levels after glucagon infusion revealed altered patterns of functional connectivity only in a small region of the posterior default mode network, while the rest of the networks appeared unaffected. Furthermore, low blood glucose was associated with changes in the right frontoparietal network after cognitive effort. Our results suggest that fasting has only limited impact on intrinsic brain activity, while a detrimental impact on a network related to attention is only observable following cognitive effort, which is in line with ego depletion and its reliance on glucose.
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Affiliation(s)
- Stelios Orfanos
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany. .,Jülich Aachen Research Alliance (JARA) - BRAIN Institute Brain Structure-Function Relationships: Decoding the Human Brain at systemic levels, Forschungszentrum Jülich GmbH and RWTH Aachen University, Jülich, Germany.
| | - Timur Toygar
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany.,Department of Biology, RWTH Aachen University, 52074, Aachen, Germany
| | - Mark Berthold-Losleben
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany.,Jülich Aachen Research Alliance (JARA) - BRAIN Institute Brain Structure-Function Relationships: Decoding the Human Brain at systemic levels, Forschungszentrum Jülich GmbH and RWTH Aachen University, Jülich, Germany
| | - Natalya Chechko
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany.,Jülich Aachen Research Alliance (JARA) - BRAIN Institute Brain Structure-Function Relationships: Decoding the Human Brain at systemic levels, Forschungszentrum Jülich GmbH and RWTH Aachen University, Jülich, Germany
| | - Annette Durst
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany.,Jülich Aachen Research Alliance (JARA) - BRAIN Institute Brain Structure-Function Relationships: Decoding the Human Brain at systemic levels, Forschungszentrum Jülich GmbH and RWTH Aachen University, Jülich, Germany
| | - Zacharias G Laoutidis
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany.,Department of Psychiatry and Psychotherapy, University of Düsseldorf, Bergische Landstrasse 2, 40629, Düsseldorf, Germany
| | - Sebastian Vocke
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany.,Jülich Aachen Research Alliance (JARA) - BRAIN Institute Brain Structure-Function Relationships: Decoding the Human Brain at systemic levels, Forschungszentrum Jülich GmbH and RWTH Aachen University, Jülich, Germany
| | - Caren Weidenfeld
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany.,Jülich Aachen Research Alliance (JARA) - BRAIN Institute Brain Structure-Function Relationships: Decoding the Human Brain at systemic levels, Forschungszentrum Jülich GmbH and RWTH Aachen University, Jülich, Germany
| | - Frank Schneider
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany.,Jülich Aachen Research Alliance (JARA) - BRAIN Institute Brain Structure-Function Relationships: Decoding the Human Brain at systemic levels, Forschungszentrum Jülich GmbH and RWTH Aachen University, Jülich, Germany
| | - Wolfram Karges
- Division of Endocrinology and Diabetes, Medical Faculty, RWTH Aachen University, 52074, Aachen, Germany
| | - Christian F Beckmann
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Centre for Functional MRI of the Brain (FMRIB), University of Oxford, Oxford, UK
| | - Ute Habel
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany.,Jülich Aachen Research Alliance (JARA) - BRAIN Institute Brain Structure-Function Relationships: Decoding the Human Brain at systemic levels, Forschungszentrum Jülich GmbH and RWTH Aachen University, Jülich, Germany
| | - Nils Kohn
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany.,Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
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4
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Amirian M, Sajadi E, Rostami P, Chaloosi M. Effect of prenatal stress (immobilization) on blood glucose levels and body weight. Int J Diabetes Dev Ctries 2014. [DOI: 10.1007/s13410-014-0214-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Abstract
Obesity is the most common nutritional disorder of cats and is a risk factor for diabetes. Similar to developments in obese people, obese cats show peripheral tissue insulin resistance and may demonstrate glucose intolerance when challenged with pharmacological amounts of glucose. However, they compensate well for the insulin resistance and do not show elevated glucose concentrations when monitored during their regular daily routine, including postprandial periods. This is possible because obese cats in the fasted and postprandial state are able to maintain hepatic insulin sensitivity and decrease endogenous glucose production, which allows them to maintain normoglycemia. Also dissimilar to what is seen in many obese humans, cats do not develop atherosclerosis and clinical hypertension. The time course for progression to overt diabetes of obese cats is unknown. One might speculate that diabetes develops when the liver finally becomes insulin resistant and/or insulin secretion becomes too low to overcome increased glucose production. In addition, amyloid, demonstrated to be deposited in islet of chronically obese cats, may contribute to a reduction in insulin secretion by reducing functional β-cell mass.
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Affiliation(s)
- Margarethe Hoenig
- College of Veterinary Medicine, University of Illinois, Urbana, Illinois 61802, USA.
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6
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Sharara-Chami RI, Zhou Y, Ebert S, Pacak K, Ozcan U, Majzoub JA. Epinephrine deficiency results in intact glucose counter-regulation, severe hepatic steatosis and possible defective autophagy in fasting mice. Int J Biochem Cell Biol 2012; 44:905-13. [PMID: 22405854 DOI: 10.1016/j.biocel.2012.02.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 02/15/2012] [Accepted: 02/23/2012] [Indexed: 02/07/2023]
Abstract
Epinephrine is one of the major hormones involved in glucose counter-regulation and gluconeogenesis. However, little is known about its importance in energy homeostasis during fasting. Our objective is to study the specific role of epinephrine in glucose and lipid metabolism during starvation. In our experiment, we subject regular mice and epinephrine-deficient mice to a 48-h fast then we evaluate the different metabolic responses to fasting. Our results show that epinephrine is not required for glucose counter-regulation: epinephrine-deficient mice maintain their blood glucose at normal fasting levels via glycogenolysis and gluconeogenesis, with normal fasting-induced changes in the peroxisomal activators: peroxisome proliferator activated receptor γ coactivator α (PGC-1α), fibroblast growth factor 21 (FGF-21), peroxisome proliferator activated receptor α (PPAR-α), and sterol regulatory element binding protein (SREBP-1c). However, fasted epinephrine-deficient mice develop severe ketosis and hepatic steatosis, with evidence for inhibition of hepatic autophagy, a process that normally provides essential energy via degradation of hepatic triglycerides during starvation. We conclude that, during fasting, epinephrine is not required for glucose homeostasis, lipolysis or ketogenesis. Epinephrine may have an essential role in lipid handling, possibly via an autophagy-dependent mechanism.
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Affiliation(s)
- Rana I Sharara-Chami
- Division of Critical Care Medicine, Department of Anesthesiology, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA.
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7
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Rivera N, Ramnanan CJ, An Z, Farmer T, Smith M, Farmer B, Irimia JM, Snead W, Lautz M, Roach PJ, Cherrington AD. Insulin-induced hypoglycemia increases hepatic sensitivity to glucagon in dogs. J Clin Invest 2010; 120:4425-35. [PMID: 21084754 DOI: 10.1172/jci40919] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 09/29/2010] [Indexed: 02/01/2023] Open
Abstract
In individuals with type 1 diabetes, hypoglycemia is a common consequence of overinsulinization. Under conditions of insulin-induced hypoglycemia, glucagon is the most important stimulus for hepatic glucose production. In contrast, during euglycemia, insulin potently inhibits glucagon's effect on the liver. The first aim of the present study was to determine whether low blood sugar augments glucagon's ability to increase glucose production. Using a conscious catheterized dog model, we found that hypoglycemia increased glucagon's ability to overcome the inhibitory effect of insulin on hepatic glucose production by almost 3-fold, an effect exclusively attributable to marked enhancement of the effect of glucagon on net glycogen breakdown. To investigate the molecular mechanism by which this effect comes about, we analyzed hepatic biopsies from the same animals, and found that hypoglycemia resulted in a decrease in insulin signaling. Furthermore, hypoglycemia and glucagon had an additive effect on the activation of AMPK, which was associated with altered activity of the enzymes of glycogen metabolism.
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Affiliation(s)
- Noelia Rivera
- Department of Molecular Physiology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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8
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Fagerholm V, Scheinin M, Haaparanta M. alpha2A-adrenoceptor antagonism increases insulin secretion and synergistically augments the insulinotropic effect of glibenclamide in mice. Br J Pharmacol 2008; 154:1287-96. [PMID: 18493247 DOI: 10.1038/bjp.2008.186] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE The imidazoline-type alpha2-adrenoceptor antagonists (+/-)-efaroxan and phentolamine increase insulin secretion and reduce blood glucose levels. It is not known whether they act by antagonizing pancreatic beta-cell alpha2-adrenoceptors or by alpha2-adrenoceptor-independent mechanisms. Many imidazolines inhibit the pancreatic beta-cell KATP channel, which is the molecular target of sulphonylurea drugs used in the treatment of type II diabetes. To investigate the mechanisms of action of (+/-)-efaroxan and phentolamine, alpha2A-adrenoceptor knockout (alpha2A-KO) mice were used. EXPERIMENTAL APPROACH Effects of (+/-)-efaroxan, 5 mg kg(-1), and phentolamine, 1 mg kg(-1), on blood glucose and insulin levels were compared with those of the non-imidazoline alpha2-adrenoceptor antagonist [8aR,12aS,13aS]-5,8,8a,9,10,11,12,12a,13,13a-decahydro-3-methoxy-12-(ethylsulphonyl)-6H-isoquino[2,1-g][1,6]naphthyridine (RS79948-197), 1 mg kg(-1), and the sulphonylurea glibenclamide, in alpha2A-KO and control (wild type (WT)) mice. KEY RESULTS In fed WT mice, (+/-)-efaroxan, phentolamine and RS79948-197 reduced blood glucose and increased insulin levels. Fasting abolished these effects. In fed alpha2A-KO mice, (+/-)-efaroxan, phentolamine and RS79948-197 did not alter blood glucose or insulin levels, and in fasted alpha2A-KO mice, blood glucose levels were increased. Glibenclamide, at a dose only moderately efficacious in WT mice (5 mg kg(-1)), caused severe hyperinsulinaemia and hypoglycaemia in alpha2A-KO mice. This was mimicked in WT mice by co-administration of RS79948-197 with glibenclamide. CONCLUSIONS AND IMPLICATIONS These results suggest that (+/-)-efaroxan and phentolamine increase insulin secretion by inhibition of beta-cell alpha2A-adrenoceptors, and demonstrate a critical role for alpha2A-adrenoceptors in limiting sulphonylurea-induced hyperinsulinaemia and hypoglycaemia.
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Affiliation(s)
- V Fagerholm
- Turku PET Centre/Preclinical Imaging, Turku, Finland.
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9
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Vicini P, Avogaro A, Spilker ME, Gallo A, Cobelli C. Epinephrine effects on insulin-glucose dynamics: the labeled IVGTT two-compartment minimal model approach. Am J Physiol Endocrinol Metab 2002; 283:E78-84. [PMID: 12067846 DOI: 10.1152/ajpendo.00530.2001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The hyperglycemic effects of epinephrine (Epi) are established; however, the modulation of Epi-stimulated endogenous glucose production (EGP) by glucose and insulin in vivo in humans is less clear. Our aim was to determine the effect of exogenously increased plasma Epi concentrations on insulin and glucose dynamics. In six normal control subjects, we used the labeled intravenous glucose tolerance test (IVGTT) interpreted with the two-compartment minimal model, which provides not only glucose effectiveness (S(G)(2*)), insulin sensitivity (S(I)(2*)), and plasma clearance rate (PCR) at basal state, but also the time course of EGP. Subjects were randomly studied during either saline or Epi infusion (1.5 microg/min). Exogenous Epi infusion increased plasma Epi concentration to a mean value of 2,034 +/- 138 pmol/l. During the stable-label IVGTT, plasma glucose, tracer glucose, and insulin concentrations were significantly higher in the Epi study. The hormone caused a significant (P < 0.05) reduction in PCR in the Epi state when compared with the basal state. The administration of Epi has a striking effect on EGP profiles: the nadir of the EGP profiles occurs at 21 +/- 7 min in the basal state and at 55 +/- 13 min in the Epi state (P < 0.05). In conclusion, we have shown by use of a two-compartment minimal model of glucose kinetics that elevated plasma Epi concentrations have profound effects at both hepatic and tissue levels. In particular, at the liver site, this hormone deeply affects, in a time-dependent fashion, the inhibitory effect of insulin on glucose release. Our findings may explain how even a normal subject may have the propensity to develop glucose intolerance under the influence of small increments of Epi during physiological stress.
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Affiliation(s)
- Paolo Vicini
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
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10
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Hojlund K, Wildner-Christensen M, Eshøj O, Skjaerbaek C, Holst JJ, Koldkjaer O, Møller Jensen D, Beck-Nielsen H. Reference intervals for glucose, beta-cell polypeptides, and counterregulatory factors during prolonged fasting. Am J Physiol Endocrinol Metab 2001; 280:E50-8. [PMID: 11120658 DOI: 10.1152/ajpendo.2001.280.1.e50] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To establish reference intervals for the pancreatic beta-cell response and the counterregulatory hormone response to prolonged fasting, we studied 33 healthy subjects (16 males, 17 females) during a 72-h fast. Glucose, insulin, C-peptide, and proinsulin levels decreased (P < 0.001), and the levels of counterregulatory factors increased during the fast [P < 0.05; glucagon and free fatty acids (FFA) with a linear increase and epinephrine, norepinephrine, and cortisol with a clear underlying circadian rhythm]. Growth hormone secretion increased from the first to third day of fasting (P < 0.05) but actually decreased from the second to third day of fasting (P = 0.03). Males had higher glucose and glucagon levels and lower FFA levels during the fast (P < 0.05), whereas no effect of gender on beta-cell polypeptides was observed. A high body mass index resulted in higher insulin and C-peptide levels during the fast (P < 0.05). In conclusion, we have provided reference intervals for glucoregulatory factors during a 72-h fast. We observed a diminished beta-cell response concomitant with an increased secretion of counterregulatory hormones. These results should be of clinical and scientific value in the investigation of hypoglycemic disorders.
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Affiliation(s)
- K Hojlund
- Diabetes Centre, Department of Endocrinology, Odense University Hospital, DK-5000 Odense C, Denmark.
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11
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Powell AM, Sherwin RS, Shulman GI. Impaired hormonal responses to hypoglycemia in spontaneously diabetic and recurrently hypoglycemic rats. Reversibility and stimulus specificity of the deficits. J Clin Invest 1993; 92:2667-74. [PMID: 8254023 PMCID: PMC288464 DOI: 10.1172/jci116883] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
To evaluate the roles of iatrogenic hypoglycemia and diabetes per se in the pathogenesis of defective hormonal counterregulation against hypoglycemia in insulin-dependent diabetes mellitus (IDDM), nondiabetic, and spontaneously diabetic BB/Wor rats were studied using a euglycemic/hypoglycemic clamp. In nondiabetic rats, recurrent (4 wk) insulin-induced hypoglycemia (mean daily glucose, MDG, 59 mg/dl) dramatically reduced glucagon and epinephrine responses by 84 and 94%, respectively, to a standardized glucose fall from 110 to 50 mg/dl. These deficits persisted for > 4 d after restoring normoglycemia, and were specific for hypoglycemia, with normal glucagon and epinephrine responses to arginine and hypovolemia, respectively. After 4 wk of normoglycemia, hormonal counterregulation increased, with the epinephrine, but not the glucagon response reaching control values. In diabetic BB rats (MDG 245 mg/dl with intermittent hypoglycemia), glucagon and epinephrine counterregulation were reduced by 86 and 90%, respectively. Chronic iatrogenic hypoglycemia (MDG 52 mg/dl) further suppressed counterregulation. Prospective elimination of hypoglycemia (MDG 432 mg/dl) improved, but did not normalize hormonal counterregulation. In diabetic rats, the glucagon defect appeared to be specific for hypoglycemia, whereas deficient epinephrine secretion also occurred during hypovolemia. We concluded that both recurrent hypoglycemia and the diabetic state independently lead to defective hormonal counterregulation. These data suggest that in IDDM iatrogenic hypoglycemia magnifies preexisting counterregulatory defects, thereby increasing the risk of severe hypoglycemia.
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Affiliation(s)
- A M Powell
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06510
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12
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Hoelzer DR, Dalsky GP, Clutter WE, Shah SD, Holloszy JO, Cryer PE. Glucoregulation during exercise: hypoglycemia is prevented by redundant glucoregulatory systems, sympathochromaffin activation, and changes in islet hormone secretion. J Clin Invest 1986; 77:212-21. [PMID: 3511090 PMCID: PMC423329 DOI: 10.1172/jci112279] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
During mild or moderate nonexhausting exercise, glucose utilization increases sharply but is normally matched by increased glucose production such that hypoglycemia does not occur. To test the hypothesis that redundant glucoregulatory systems including sympathochromaffin activation and changes in pancreatic islet hormone secretion underlie this precise matching, eight young adults exercised at 55-60% of maximal oxygen consumption for 60 min on separate occasions under four conditions: (a) control study (saline infusion); (b) islet clamp study (insulin and glucagon held constant by somatostatin infusion with glucagon and insulin replacement at fixed rates before, during and after exercise with insulin doses determined individually and shown to produce normal and stable plasma glucose concentrations prior to each study); (c) adrenergic blockage study (infusions of the alpha- and beta-adrenergic antagonists phentolamine and propranolol); (d) adrenergic blockade plus islet clamp study. Glucose production matched increased glucose utilization during exercise in the control study and plasma glucose did not fall (92 +/- 1 mg/dl at base line, 90 +/- 2 mg/dl at the end of exercise). Plasma glucose also did not fall during exercise when changes in insulin and glucagon were prevented in the islet clamp study. In the adrenergic blockade study, plasma glucose declined initially during exercise because of a greater initial increase in glucose utilization, then plateaued with an end-exercise value of 74 +/- 3 mg/dl (P less than 0.01 vs. control). In contrast, in the adrenergic blockade plus islet clamp study, exercise was associated with glucose production substantially lower than control and plasma glucose fell progressively to 58 +/- 7 mg/dl (P less than 0.001); end-exercise plasma glucose concentrations ranged from 34 to 72 mg/dl. Thus, we conclude that: (a) redundant glucoregulatory systems are involved in the precise matching of increased glucose utilization and glucose production that normally prevents hypoglycemia during moderate exercise in humans. (b) Sympathochromaffin activation, perhaps sympathetic neural norepinephrine release, plays a primary glucoregulatory role by limiting glucose utilization as well as stimulating glucose production. (c) Changes in pancreatic islet hormone secretion (decrements in insulin, increments in glucagon, or both) are not normally critical but become critical when catecholamine action is deficient. (d) Glucoregulation fails, and hypoglycemia can develop, both when catecholamine action is deficient and when changes in islet hormones do not occur during exercise in humans.
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