1
|
Petersen KF, Rothman DL, Shulman GI. Reply to Carter et al.: An alternative hypothesis for why exposure to static magnetic and electric fields treats type 2 diabetes. Am J Physiol Endocrinol Metab 2021; 320:E1003. [PMID: 33843277 DOI: 10.1152/ajpendo.00120.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Kitt Falk Petersen
- Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut
| | - Douglas L Rothman
- Department of Radiology & Bioengineering, Yale School of Medicine, New Haven, Connecticut
| | - Gerald I Shulman
- Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut
- Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
| |
Collapse
|
2
|
Broderick TL, Sennott JM, Gutkowska J, Jankowski M. Anti-inflammatory and angiogenic effects of exercise training in cardiac muscle of diabetic mice. Diabetes Metab Syndr Obes 2019; 12:565-573. [PMID: 31118719 PMCID: PMC6499146 DOI: 10.2147/dmso.s197127] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 03/12/2019] [Indexed: 12/27/2022] Open
Abstract
Background: Improved glycemic control and cardiovascular function are major benefits of regular exercise training (ET) in type 2 diabetes. Recent work has demonstrated that ET improves cardiac and vascular functions independent of obesity, inflammation, and glucose control in the diabetic db/db mouse. In this study, we determined whether ET can overcome the effects of elevated inflammatory cytokines and hyperglycemia on markers of cardiac angiogenesis and inflammation in the diabetic mouse. Methods: Male diabetic db/db mice were assigned to a sedentary and exercise-trained group. Sedentary lean control littermates were used as controls. ET was performed at moderate intensity on a treadmill 5 days a week for a period of 8 weeks. After ET, blood was collected for assay of glucose, hemoglobin (HB and HB1AC), C-reactive protein (CRP), and IL-6. Markers of inflammation and insulin resistance (IL-6, IL-1β, and tumor necrosis factor-alpha [TNF-α]) and angiogenesis (endothelial nitric oxide synthase [eNOS], vascular endothelial growth factor-A [VEGF-A], and hypoxia-inducible factor-1α [HIF-1α]) were measured in hearts. Results: Diabetic db/db mice remained obese and hyperglycemic after ET. Percent total HB and HB1AC were significantly higher in ET db/db mice compared to sedentary db/db mice, indicating further deterioration of glucose control with ET. Plasma levels of CRP and IL-6 were higher in sedentary db/db mice compared to control mice and were unaffected by ET. However, in the presence of hyperglycemia and elevated plasma cytokines, protein expression of eNOS, mRNA expression of VEGF-A, and HIF-1α was increased in db/db hearts after ET. On the other hand, protein expression of TNF-α and mRNA expression IL-6 and IL-1β was significantly decreased by ET in hearts of db/db mice. Conclusion: Our results indicate that ET improves cardiac markers of angiogenesis, insulin resistance, and endothelial dysfunction in the db/db mouse. This was observed independently of obesity, hyperglycemia, and the systemic inflammatory state.
Collapse
Affiliation(s)
- Tom L Broderick
- Laboratory of Diabetes and Exercise Metabolism, Department of Physiology, College of Graduate Studies, Midwestern University, Glendale, AZ, USA
- Correspondence: Tom L BroderickLaboratory of Diabetes and Exercise Metabolism, Department of Physiology, College of Graduate Studies, Midwestern University, 19555 North 59 Avenue, Glendale, AZ85308, USATel +1 623 572 3664Fax +1 623 572 3673Email
| | - Jacqueline M Sennott
- Department of Cardiology, Medical Education H23, Saint-Joseph Mercy Health System, Pontiac, MI, USA
| | - Jolanta Gutkowska
- Cardiovascular Biochemistry Laboratory, CRCHUM (7-134), Department of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Marek Jankowski
- Cardiovascular Biochemistry Laboratory, CRCHUM (7-134), Department of Medicine, University of Montreal, Montreal, Quebec, Canada
| |
Collapse
|
3
|
Sim YB, Park SH, Kim SS, Lim SM, Jung JS, Sharma N, Suh HW. Spinal β-adrenergic receptors' activation increases the blood glucose level in mice. Anim Cells Syst (Seoul) 2017; 21:278-285. [PMID: 30460079 PMCID: PMC6138324 DOI: 10.1080/19768354.2017.1345788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 05/12/2017] [Accepted: 05/25/2017] [Indexed: 10/26/2022] Open
Abstract
We examined the role of spinally located β-adrenergic receptors in the regulation of the blood glucose level. The intrathecal (i.t.) injections with dobutamine (β1-adrenergic receptor agonist) or terbutaline (β2-adrenergic receptor agonist) caused an elevation of the blood glucose level, whereas metoprolol (β1-adrenergic receptor antagonist) or butoxamine (β2-adrenergic receptor antagonist) did not. In addition, i.t. pretreatment with pertussis toxin (PTX) attenuated the hyperglycemic effect induced by dobutamine or terbutaline. Moreover, plasma insulin level was increased by dobutamine but not by terbutaline, and PTX reduced dobutamine-induced up-regulation of the plasma insulin level. Terbutaline significantly increased plasma corticosterone level, and PTX further enhanced terbutaline-induced corticosterone level. Furthermore, intraperitoneal (i.p.) pretreatment with hexamethonium- (a preganglionic blocker) attenuated dobutamine- and terbutaline-induced hyperglycemic effects. Our results suggest that activation of spinal β1- and β2-adrenergic receptors produces hyperglycemic effects in a different manner. Spinally located PTX-sensitive G-proteins appear to be involved in hyperglycemic effect induced by terbutaline. Furthermore, dobutamine- or terbutaline-induced hyperglycemia appears to be mediated through the spinal nerves.
Collapse
Affiliation(s)
- Yun-Beom Sim
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Soo-Hyun Park
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Sung-Su Kim
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Su-Min Lim
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Jun-Sub Jung
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Naveen Sharma
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Hong-Won Suh
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| |
Collapse
|
4
|
Martin RE, Aebi JD, Hornsperger B, Krebs HJ, Kuhn B, Kuglstatter A, Alker AM, Märki HP, Müller S, Burger D, Ottaviani G, Riboulet W, Verry P, Tan X, Amrein K, Mayweg AV. Discovery of 4-Aryl-5,6,7,8-tetrahydroisoquinolines as Potent, Selective, and Orally Active Aldosterone Synthase (CYP11B2) Inhibitors: In Vivo Evaluation in Rodents and Cynomolgus Monkeys. J Med Chem 2015; 58:8054-65. [PMID: 26403853 DOI: 10.1021/acs.jmedchem.5b00851] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Inappropriately high levels of aldosterone are associated with many serious medical conditions, including renal and cardiac failure. A focused screen hit has been optimized into a potent and selective aldosterone synthase (CYP11B2) inhibitor with in vitro activity against rat, mouse, human, and cynomolgus monkey enzymes, showing a selectivity factor of 160 against cytochrome CYP11B1 in the last species. The novel tetrahydroisoquinoline compound (+)-(R)-6 selectively reduced aldosterone plasma levels in vivo in a dose-dependent manner in db/db mice and cynomolgus monkeys. The selectivity against CYP11B1 as predicted by cellular inhibition data and free plasma fraction translated well to Synacthen challenged cynomolgus monkeys up to a dose of 0.1 mg kg(-1). This compound, displaying good in vivo potency and selectivity in mice and monkeys, is ideally suited to perform mechanistic studies in relevant rodent models and to provide the information necessary for translation to non-human primates and ultimately to man.
Collapse
Affiliation(s)
- Rainer E Martin
- Medicinal Chemistry, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Johannes D Aebi
- Medicinal Chemistry, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Benoit Hornsperger
- Medicinal Chemistry, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Hans-Jakob Krebs
- Medicinal Chemistry, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Bernd Kuhn
- Medicinal Chemistry, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Andreas Kuglstatter
- Medicinal Chemistry, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - André M Alker
- Medicinal Chemistry, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Hans Peter Märki
- Medicinal Chemistry, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Stephan Müller
- Discovery Technologies, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Dominique Burger
- Discovery Technologies, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Giorgio Ottaviani
- Pharmaceutical Sciences, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Shanghai, F. Hoffmann-La Roche Ltd. , 720 Cai Lun Road, Building 5, Pudong, Shanghai 201203, China
| | - William Riboulet
- Neuroscience, Ophthalmology and Rare Diseases, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Philippe Verry
- Discovery Cardiovascular and Metabolic Disease, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Xuefei Tan
- Medicinal Chemistry, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Shanghai, F. Hoffmann-La Roche Ltd. , 720 Cai Lun Road, Building 5, Pudong, Shanghai 201203, China
| | - Kurt Amrein
- Discovery Infectious Disease, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Alexander V Mayweg
- Medicinal Chemistry, Roche Pharma Research and Early Development (pRED), Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd. , Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| |
Collapse
|
5
|
Chong AC, Vogt MC, Hill AS, Brüning JC, Zeltser LM. Central insulin signaling modulates hypothalamus-pituitary-adrenal axis responsiveness. Mol Metab 2014; 4:83-92. [PMID: 25685696 PMCID: PMC4314547 DOI: 10.1016/j.molmet.2014.12.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 11/26/2014] [Accepted: 12/01/2014] [Indexed: 12/29/2022] Open
Abstract
Objective Obesity is often accompanied by hyperactivity of the neuroendocrine stress axis and has been linked to an increased risk of psychiatric disorders. Insulin is reciprocally regulated with the stress hormone corticosterone (CORT), raising the possibility that insulin normally provides inhibitory tone to the hypothalamus-adrenal-pituitary (HPA) axis. Here we examined whether disrupting signaling via the insulin receptor (InsR) in hypothalamic subpopulations impacts the neuroendocrine response to acute psychological stress. Methods We used Nkx2.1-Cre, Sim1-Cre and Agrp-Cre transgenic driver lines to generate conditional knockouts of InsR signaling throughout the hypothalamus, paraventricular nucleus of the hypothalamus (PVH) and in neurons expressing Agouti-related peptide (AgRP) in the arcuate nucleus of the hypothalamus (ARH), respectively. We used a combination of molecular, behavioral and neuroendocrine criteria to evaluate the consequences on HPA axis responsiveness. Results Endpoints related to body weight and glucose homeostasis were not altered in any of the conditional mutant lines. Consistent with observations in the neuronal Insr knockout mice (NIRKO), baseline levels of serum CORT were similar to controls in all three lines. In male mice with broad disruptions of InsR signals in Nkx2.1-expressing regions of the hypothalamus (IRNkx2.1 KO), we observed elevated arginine vasopressin (AVP) levels at baseline and heightened neuroendocrine responses to restraint stress. IRNkx2.1 KO males also exhibited increased anxiety-like behaviors in open field, marble burying, and stress-induced hyperthermia testing paradigms. HPA axis responsivity was not altered in IRSim1 KO males, in which InsR was disrupted in the PVH. In contrast to observations in the IRNkx2.1 KO males, disrupting InsR signals in ARH neurons expressing Agrp (IRAgrp KO) led to reduced AVP release in the median eminence (ME). Conclusions We find that central InsR signals modulate HPA responsivity to restraint stress. InsR signaling in AgRP/NPY neurons appears to promote AVP release, while signaling in other hypothalamic neuron(s) likely acts in an opposing fashion. Alterations in InsR signals in neurons that integrate metabolic and psychiatric information could contribute to the high co-morbidity of obesity and mental disorders.
Collapse
Key Words
- ACTH, adrenocorticotropic hormone
- ARH, arcuate nucleus of the hypothalamus
- AVP, arginine vasopressin
- AgRP
- AgRP, agouti-related peptide
- CORT, corticosterone
- CRH, corticotropin-releasing hormone
- FST, forced swim test
- Gr, Glucocorticoid receptor
- HPA axis
- HPA axis, Hypothalamus–Pituitary–Adrenal axis
- Hypothalamus
- IRAgrp KO, knockout of InsR using Agrp-Cre
- IRNkx2.1 KO, knockout of InsR using Nkx2.1-Cre
- IRSim1 KO, knockout of InsR using Sim1-Cre
- InsR, insulin receptor
- Insulin
- MB, marble burying test
- MBH, mediobasal hypothalamus
- ME, median eminence
- NPY, neuropeptide Y
- NSF, novelty suppressed feeding test
- OF, open field test
- POMC, pro-opiomelanocortin
- SIH, stress-induced hyperthermia test
- Stress response
Collapse
Affiliation(s)
- Angie C.N. Chong
- Naomi Berrie Diabetes Center, Columbia University, New York, NY 10032, USA
| | - Merly C. Vogt
- Max-Planck-Institute for Metabolism Research, 50931 Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50674 Cologne, Germany
| | - Alexis S. Hill
- Division of Integrative Neuroscience, Departments of Neuroscience and Psychiatry, Department of Pharmacology, Columbia University New York, NY 10032, USA
| | - Jens C. Brüning
- Max-Planck-Institute for Metabolism Research, 50931 Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50674 Cologne, Germany
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, 50924 Cologne, Germany
| | - Lori M. Zeltser
- Naomi Berrie Diabetes Center, Columbia University, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
- Corresponding author. Naomi Berrie Diabetes Center, Columbia University, 1150 St Nicholas Ave, New York, NY 10032, USA. Tel.: +1 (212) 851 5314; fax: +1 (212) 851 6306.
| |
Collapse
|
6
|
Sim YB, Park SH, Kim SS, Lim SM, Jung JS, Suh HW. Activation of spinal α2 adrenergic receptors induces hyperglycemia in mouse though activating sympathetic outflow. Eur J Pharmacol 2014; 741:316-22. [DOI: 10.1016/j.ejphar.2014.08.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 08/19/2014] [Accepted: 08/20/2014] [Indexed: 11/28/2022]
|
7
|
Sim YB, Park SH, Kim SS, Lim SM, Jung JS, Lee JK, Suh HW. Pertussis toxin administered spinally induces a hypoglycemic effect on normal and diabetic mice. Pharmacology 2014; 94:29-40. [PMID: 25171426 DOI: 10.1159/000363578] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 05/13/2014] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS To show whether intrathecal (i.t.) treatment with pertussis toxin (PTX) produces a hypoglycemic effect in ICR, db/db and streptozotocin-treated mice. METHODS The blood glucose level (BGL) was measured after i.t. treatment with PTX, AB5 toxins and PTX subunits. Insulin or leptin levels were measured after PTX injection. The effect of PTX on the BGL was examined in adrenalectomized (ADX) mice. Glucose transporter (GLUT) levels were determined by Western blotting. RESULTS PTX attenuated the elevated BGL in the D-glucose-fed model in a long-term manner. Heat-labile toxin (HLT), HLT subunit B or Shiga toxin, which belong to the AB5 toxins, administered i.t. did not affect the BGL. PTX A protomer (PTX-A) or PTX B oligomers (PTX-B) injected i.t. did not have an effect on the BGL as well. However, combined treatment with PTX-A and PTX-B subunits caused a hypoglycemic effect. The leptin level was gradually reduced by PTX for up to 6 days, without affecting the insulin level. PTX administered i.t. significantly decreased the BGL further in ADX mice. Moreover, GLUT-2 (hypothalamus and pituitary gland), GLUT-4 (muscle) and GLUT-3 (adrenal gland) expression levels were increased, whereas GLUT-1 (brain cortex, liver, muscle and spinal cord), GLUT-2 (liver) and GLUT-3 (brain cortex and pituitary gland) expression levels were decreased. DISCUSSION Our data suggest that PTX administered spinally produces a hypoglycemic effect in a long-term manner, and PTX-induced hypoglycemia appears to be mediated by the reduction in activity of the glucocorticoid system. Furthermore, PTX may modulate the insulin level during hypoglycemia. Among GLUTs, GLUT-4 in muscle, GLUT-2 in the liver, hypothalamus and pituitary gland as well as GLUT-1 in the adrenal gland may be responsible for PTX-induced hypoglycemia.
Collapse
Affiliation(s)
- Yun-Beom Sim
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | | | | | | | | | | | | |
Collapse
|
8
|
Perry RJ, Zhang XM, Zhang D, Kumashiro N, Camporez JPG, Cline GW, Rothman DL, Shulman GI. Leptin reverses diabetes by suppression of the hypothalamic-pituitary-adrenal axis. Nat Med 2014; 20:759-63. [PMID: 24929951 PMCID: PMC4344321 DOI: 10.1038/nm.3579] [Citation(s) in RCA: 145] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 04/21/2014] [Indexed: 12/14/2022]
Abstract
Leptin treatment reverses hyperglycemia in animal models of poorly controlled type 1 diabetes (T1D), spurring great interest in the possibility of treating patients with this hormone. The antidiabetic effect of leptin has been postulated to occur through suppression of glucagon production, suppression of glucagon responsiveness or both; however, there does not appear to be a direct effect of leptin on the pancreatic alpha cell. Thus, the mechanisms responsible for the antidiabetic effect of leptin remain poorly understood. We quantified liver-specific rates of hepatic gluconeogenesis and substrate oxidation in conjunction with rates of whole-body acetate, glycerol and fatty acid turnover in three rat models of poorly controlled diabetes, including a model of diabetic ketoacidosis. We show that the higher rates of hepatic gluconeogenesis in all these models could be attributed to hypoleptinemia-induced activity of the hypothalamic-pituitary-adrenal (HPA) axis, resulting in higher rates of adipocyte lipolysis, hepatic conversion of glycerol to glucose through a substrate push mechanism and conversion of pyruvate to glucose through greater hepatic acetyl-CoA allosteric activation of pyruvate carboxylase flux. Notably, these effects could be dissociated from changes in plasma insulin and glucagon concentrations and hepatic gluconeogenic protein expression. All the altered systemic and hepatic metabolic fluxes could be mimicked by infusing rats with Intralipid or corticosterone and were corrected by leptin replacement. These data demonstrate a critical role for lipolysis and substrate delivery to the liver, secondary to hypoleptinemia and HPA axis activity, in promoting higher hepatic gluconeogenesis and hyperglycemia in poorly controlled diabetes.
Collapse
Affiliation(s)
- Rachel J. Perry
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT
| | - Xian-Man Zhang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT
| | - Dongyan Zhang
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT
| | - Naoki Kumashiro
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT
| | | | - Gary W. Cline
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT
| | - Douglas L. Rothman
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT
- Department of Biomedical Engineering, Yale University School of Medicine, New Haven, CT
| | - Gerald I. Shulman
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT
- Novo Nordisk Center for Basic Metabolic Research, Copenhagen, DK
| |
Collapse
|
9
|
Brust KB, Corbell KA, Al-Nakkash L, Babu JR, Broderick TL. Expression of gluconeogenic enzymes and 11β-hydroxysteroid dehydrogenase type 1 in liver of diabetic mice after acute exercise. Diabetes Metab Syndr Obes 2014; 7:495-504. [PMID: 25364268 PMCID: PMC4211855 DOI: 10.2147/dmso.s70767] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
During acute exercise, normoglycemia is maintained by a precise match between hepatic glucose production and its peripheral utilization. This is met by a complex interplay of hepatic responses and glucose uptake by muscle. However, the effect of a single bout of exercise on hepatic gluconeogenesis, corticosterone (CORT) secretion, and glucose homeostasis in the db/db mouse model of type 2 diabetes is poorly understood. Diabetic db/db and lean control littermates were subjected to a 30 minute session of treadmill running and sacrificed either immediately after exercise or 8 hours later. Plasma glucose levels were markedly increased in db/db mice after exercise, whereas no change in glucose was observed in lean mice. Post-exercise measurements revealed that plasma CORT levels were also significantly increased in db/db mice compared to lean mice. Plasma hypothalamic corticotropin releasing hormone and pituitary adrenocorticotropic hormone levels were reciprocally decreased in both db/db and lean mice after exercise, indicating intact feedback mechanisms. Protein expression, determined by Western blot analysis, of the glucocorticoid receptor in liver was significantly increased in db/db mice subjected to prior exercise. In liver of db/db mice, a significant increase in the expression of phosphoenolpyruvate carboxykinase was noted compared to lean mice after exercise. However, no change in the expression of glucose-6-phosphatase (G6Pase) α or β was observed in db/db mice. Expression of 11β-hydroxysteroid dehydrogenase type 1 was increased significantly in db/db mice compared to lean mice after exercise. Our results show differences in plasma glucose and protein expression of gluconeogenic enzymes after acute exercise between lean and diabetic db/db mice. The db/db diabetic mouse is hyperglycemic after acute exercise. This hyperglycemic state may be explained, in part, by enhanced endogenous CORT secretion and regulated hepatic phosphoenolpyruvate carboxykinase and 11β-hydroxysteroid dehydrogenase type 1 protein expression.
Collapse
Affiliation(s)
- Korie B Brust
- Department of Biomedical Sciences, College of Health Sciences, Midwestern University, Glendale, AZ, USA
| | - Kathryn A Corbell
- Department of Physiology, College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USA
| | - Layla Al-Nakkash
- Department of Physiology, College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USA
| | - Jeganathan Ramesh Babu
- Department of Nutrition, Dietetics, and Hospitality Management, Auburn University, Auburn, AL, USA
| | - Tom L Broderick
- Department of Physiology, College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USA
- Laboratory of Diabetes and Exercise Metabolism, Midwestern University, Glendale, AZ, USA
- Correspondence: Tom L Broderick, Department of Physiology, Laboratory of Diabetes and Exercise Metabolism, Midwestern University, 19555 North 59th Avenue, Glendale, AZ, 85308, USA, Tel +1 623 572 3664, Fax +1 623 572 3673, Email
| |
Collapse
|
10
|
Broderick TL, Jankowski M, Wang D, Danalache BA, Parrott CR, Gutkowska J. Downregulation in GATA4 and Downstream Structural and Contractile Genes in the db/db Mouse Heart. ISRN ENDOCRINOLOGY 2012; 2012:736860. [PMID: 22474596 PMCID: PMC3313578 DOI: 10.5402/2012/736860] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 01/02/2012] [Indexed: 01/25/2023]
Abstract
Reduced expression of GATA4, a transcriptional factor for structural and cardioprotective genes, has been proposed as a factor contributing to the development of cardiomyopathy. We investigated whether the reduction of cardiac GATA4 expression reported in diabetes alters the expression of downstream genes, namely, atrial natriuretic peptide (ANP), B-type natriuretic, peptide (BNP), and α- and β-myosin heavy chain (MHC). db/db mice, a model of type 2 diabetes, with lean littermates serving as controls, were studied. db/db mice exhibited obesity, hyperglycemia, and reduced protein expression of cardiac GLUT4 and IRAP (insulin-regulated aminopeptidase), the structural protein cosecreted with GLUT4. Hearts from db/db mice had reduced protein expression of GATA4 (~35%) with accompanying reductions in mRNA expression of ANP (~40%), BNP (~85%), and α-MHC mRNA (~50%) whereas expression of β-MHC mRNA was increased by ~60%. Low GATA4 was not explained by an increased ligase or atrogin1 expression. CHIP protein content was modestly downregulated (27%) in db/db mice whereas mRNA and protein expression of the CHIP cochaperone HSP70 was significantly decreased in db/db hearts. Our results indicate that low GATA4 in db/db mouse heart is accompanied by reduced expression of GATA4-regulated cardioprotective and structural genes, which may explain the development of cardiomyopathy in diabetes.
Collapse
Affiliation(s)
- Tom L Broderick
- Laboratory of Diabetes and Exercise Metabolism, Department of Physiology, Midwestern University, 19555 North 59th Avenue, Glendale, AZ, 85308, USA
| | | | | | | | | | | |
Collapse
|
11
|
Hancock SD, Olmstead MC. Animal Models of Eating Disorders. ANIMAL MODELS OF DRUG ADDICTION 2011. [DOI: 10.1007/978-1-60761-934-5_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
|
12
|
Parrott CR, Ghosh P, Tedeschi J, Gunasekara G, Broderick TL. Urinary corticosterone and normetanephrine levels after voluntary wheel and forced treadmill running in the db/db mouse. ACTA ACUST UNITED AC 2011. [DOI: 10.4236/jdm.2011.14011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
13
|
Fasting hyperglycemia is not associated with increased expression of PEPCK or G6Pc in patients with Type 2 Diabetes. Proc Natl Acad Sci U S A 2009; 106:12121-6. [PMID: 19587243 DOI: 10.1073/pnas.0812547106] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Fasting hyperglycemia in patients with type 2 diabetes mellitus (T2DM) is attributed to increased hepatic gluconeogenesis, which has been ascribed to increased transcriptional expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase, catalytic (G6Pc). To test this hypothesis, we examined hepatic expression of these 2 key gluconeogenic enzymes in 2 rodent models of fasting hyperglycemia and in patients with T2DM. In rats, high-fat feeding (HFF) induces insulin resistance but a robust beta-cell response prevents hyperglycemia. Fasting hyperglycemia was induced in the first rat model by using nicotinamide and streptozotocin to prevent beta-cell compensation, in combination with HFF (STZ/HFF). In a second model, control and HFF rats were infused with somatostatin, followed by portal vein infusion of insulin and glucagon. Finally, the expression of these enzymes was measured in liver biopsy samples obtained from insulin sensitive, insulin resistant, and untreated T2DM patients undergoing bariatric surgery. Rats treated with STZ/HFF developed modest fasting hyperglycemia (119 +/- 4 vs. 153 +/- 6 mg/dL, P < 0.001) and increased rates of endogenous glucose production (EGP) (4.6 +/- 0.6 vs. 6.9 +/- 0.6 mg/kg/min, P = 0.02). Surprisingly, the expression of PEPCK or G6Pc was not increased. Matching plasma insulin and glucagon with portal infusions led to higher plasma glucoses in the HFF rats (147 +/- 4 vs. 161 +/- 4 mg/dL, P = 0.05) with higher rates of EGP and gluconeogenesis. However, PEPCK and G6Pc expression remained unchanged. Finally, in patients with T2DM, hepatic expression of PEPCK or G6Pc was not increased. Thus, in contrast to current dogma, these data demonstrate that increased transcriptional expression of PEPCK1 and G6Pc does not account for increased gluconeogenesis and fasting hyperglycemia in patients with T2DM.
Collapse
|
14
|
Sennott J, Morrissey J, Standley PR, Broderick TL. Treadmill exercise training fails to reverse defects in glucose, insulin and muscle GLUT4 content in the db/db mouse model of diabetes. ACTA ACUST UNITED AC 2008; 15:173-9. [PMID: 18653321 DOI: 10.1016/j.pathophys.2008.06.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 06/16/2008] [Accepted: 06/18/2008] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Regular exercise is recommended for the treatment of type 2 diabetes because of the benefits on body weight and glycemic control. The present study was designed to compare the impact of voluntary wheel and forced treadmill running on the metabolic state in the db/db mouse model of type 2 diabetes. Our hypothesis is that voluntary exercise training reduces body weight, blood glucose and insulin levels and restores GLUT4 levels in skeletal muscle, whereas forced exercise training produces a greater effect. STUDY DESIGN Male diabetic db/db mice were assigned to sedentary (DS), voluntary wheel running (DV), and forced treadmill running (DT) groups for 12 weeks. Nondiabetic heterozygote littermates served as control (CN). RESULTS Over the 12-week period, DV and DT mice ran a total of 4.24+/-0.18km and 11.8km, respectively. At week 12, fasting plasma glucose was decreased in DV mice compared to DS mice and occurred in the absence weight loss. In DT mice, body weight and fasting plasma glucose were not improved with exercise when compared to DS mice and were actually higher compared to DV mice. After training, fasting plasma insulin was increased in DS mice compared to CN mice and training failed to normalize plasma insulin levels. Gastrocnemius GLUT4 content was reduced in DS mice compared to CN mice and training had no effect in preventing this depression from occurring. CONCLUSION The results of this study indicate that while voluntary exercise improved only blood glucose, forced treadmill exercise training failed to restore body weight, blood glucose and insulin, and muscle GLUT4 content.
Collapse
Affiliation(s)
- Jacqueline Sennott
- Midwestern University, Laboratory of Diabetes and Exercise Metabolism, Department of Physiology, 19555 North 59th Avenue, Glendale, AZ 85308, United States
| | | | | | | |
Collapse
|
15
|
Palmer G, Aurrand-Lions M, Contassot E, Talabot-Ayer D, Ducrest-Gay D, Vesin C, Chobaz-Péclat V, Busso N, Gabay C. Indirect effects of leptin receptor deficiency on lymphocyte populations and immune response in db/db mice. THE JOURNAL OF IMMUNOLOGY 2006; 177:2899-907. [PMID: 16920925 DOI: 10.4049/jimmunol.177.5.2899] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Leptin-deficient ob/ob and leptin receptor (Ob-rb)-deficient db/db mice display a marked thymic atrophy and exhibit defective immune responses. Lymphocytes express leptin receptors and leptin exerts direct effects on T cells in vitro. In addition, ob/ob and db/db mice display multiple neuroendocrine and metabolic defects, through which leptin deficiency may indirectly affect the immune system in vivo. To study the relative contributions of direct and indirect effects of leptin on the immune system in a normal environment, we generated bone marrow chimeras (BMCs) by transplantation of leptin receptor-deficient db/db, or control db/+, bone marrow cells into wild-type (WT) recipients. The size and cellularity of the thymus, as well as cellular and humoral immune responses, were similar in db/db to WT and db/+ to WT BMCs. The immune phenotype of db/db mice is thus not explained by a cell autonomous defect of db/db lymphocytes. Conversely, thymus weight and cell number were decreased in the reverse graft setting in WT to db/db BMCs, indicating that expression of the leptin receptor in the environment is important for T cell development. Finally, normal thymocyte development occurred in fetal db/db thymi transplanted into WT hosts, indicating that direct effects of leptin are not required locally in the thymic microenvironment. In conclusion, direct effects of leptin on bone marrow-derived cells and on thymic stromal cells are not necessary for T lymphocyte maturation in normal mice. In contrast, leptin receptor deficiency affects the immune system indirectly via changes in the systemic environment.
Collapse
Affiliation(s)
- Gaby Palmer
- Department of Pathology and Immunology, University of Geneva School of Medicine, Switzerland
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Hsu HT, Chang YC, Chiu YN, Liu CL, Chang KJ, Guo IC. Leptin interferes with adrenocorticotropin/3',5'-cyclic adenosine monophosphate (cAMP) signaling, possibly through a Janus kinase 2-phosphatidylinositol 3-kinase/Akt-phosphodiesterase 3-cAMP pathway, to down-regulate cholesterol side-chain cleavage cytochrome P450 enzyme in human adrenocortical NCI-H295 cell line. J Clin Endocrinol Metab 2006; 91:2761-9. [PMID: 16684834 DOI: 10.1210/jc.2005-2383] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Obesity has adverse effects on adrenocortical functions. Adipocyte-derived leptin, a biomarker molecule of obesity, may directly control adrenal steroidogenesis via an unclear mechanism. OBJECTIVE We studied the mechanism underlying leptin action on adrenal steroidogenesis in human adrenocortical NCI-H295 tumor cell line. METHODS Levels of progesterone, cortisol, and cAMP were determined by ELISA. Western blotting was used to detect protein amounts of P450 side-chain cleavage (P450scc), Janus kinase 2 (JAK2), Akt, and their phosphorylated forms. The mRNA expressions of P450scc and leptin receptors were measured by RT-PCR and real-time PCR. P450scc promoter activity was analyzed with a luciferase reporter system. RESULTS Cholera toxin mimicked ACTH action by increasing adrenal cAMP levels and steroid secretion. Leptin did not affect basal release but significantly inhibited ACTH/cholera toxin-induced steroid secretion. The concomitant inhibitions by leptin on cholera toxin-induced protein and ACTH/cholera toxin-induced mRNA expression of P450scc were confirmed. Leptin inhibited ACTH/cholera toxin-induced CYP11A1 promoter activity via a known cAMP-responsive region located between -1.7 and -1.5 kb. Leptin activated phosphorylations of JAK2 and Akt. Inhibitory effects of leptin on ACTH/cholera toxin-induced cAMP levels, CYP11A1 promoter activity, and steroid secretion were blunted by either inhibitor of JAK2 (AG490) or phosphatidylinositol 3-kinase/Akt (wortmannin) as well as inhibitors of cAMP-degrading phosphodiesterases (PDEs), including nonspecific 3-isobutyl-1-methylxanthine and PDE3-specific SKF94836. Leptin failed to affect the inductions of CYP11A1 promoter activity and steroid secretion by PDE-nonhydrolyzable N(6)-monobutyryl-cAMP. CONCLUSIONS Leptin interferes with ACTH/cAMP signaling, possibly through a cAMP-degrading mechanism involving activation of JAK2, phosphatidylinositol 3-kinase, and PDE3, to down-regulate P450scc expression and consequent adrenal steroidogenesis.
Collapse
Affiliation(s)
- Hao-Ting Hsu
- Department of Veterinary Medicine, College of Bio-Resources and Agriculture, National Taiwan University, Taipei 10617, Taiwan
| | | | | | | | | | | |
Collapse
|
17
|
Abstract
Leptin is produced primarily by adipocytes and functions in a feedback loop regulating body weight. Leptin deficiency results in severe obesity and a variety of endocrine abnormalities in animals and humans. Several studies indicated that leptin plays an important role in immune responses. It exerts protective anti-inflammatory effects in models of acute inflammation and during activation of innate immune responses. In contrast, leptin stimulates T lymphocyte responses, thus having rather a proinflammatory role in experimental models of autoimmune diseases. Clinical studies have so far yielded inconsistent results, suggesting a rather complex role for leptin in immune-mediated inflammatory conditions in humans.
Collapse
Affiliation(s)
- Eiva Bernotiene
- Department of Experimental Research, Institute of Experimental and Clinical Medicine, Vilnius University, Vilnius, Lithuania
| | - Gaby Palmer
- Division of Rheumatology, Department of Internal Medicine, University Hospital, Geneva, Switzerland
- Department of Pathology and Immunology, University of Geneva School of Medicine, Geneva, Switzerland
| | - Cem Gabay
- Division of Rheumatology, Department of Internal Medicine, University Hospital, Geneva, Switzerland
- Department of Pathology and Immunology, University of Geneva School of Medicine, Geneva, Switzerland
| |
Collapse
|
18
|
Kuriyama K, Sasahara K, Kudo T, Shibata S. Daily injection of insulin attenuated impairment of liver circadian clock oscillation in the streptozotocin-treated diabetic mouse. FEBS Lett 2004; 572:206-10. [PMID: 15304349 DOI: 10.1016/j.febslet.2004.07.036] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2004] [Revised: 06/24/2004] [Accepted: 07/16/2004] [Indexed: 10/26/2022]
Abstract
Recent studies have shown a dampened amplitude of clock gene rhythm in the heart and liver of streptozotocin (STZ)-treated rats and mice, however it is unknown whether impairment is due to dysfunction of the suprachiasmatic nucleus (SCN) or not. Rhythmic expression of mPER2 was dampened in the STZ-treated mouse liver but not SCN and cerebral cortex. Injection of insulin could normalize an impairment of mPer2 and mPER2 expression rhythm in the liver, when it was injected at nighttime, but not at daytime. In the present study, we demonstrated that insulin-dependent diabetes impaired oscillation of the peripheral clock gene and its product. Insulin injection can recover dampened oscillation of the peripheral clock depending on its injection time.
Collapse
Affiliation(s)
- Koji Kuriyama
- Department of Pharmacology, School of Science and Engineering, Waseda University, Higashifusimi 2-7-5, Nishitokyo-Shi 202-0021, Japan
| | | | | | | |
Collapse
|
19
|
Delayed resolution of acute inflammation during zymosan-induced arthritis in leptin-deficient mice. Arthritis Res Ther 2004; 6:R256-63. [PMID: 15142272 PMCID: PMC416449 DOI: 10.1186/ar1174] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2003] [Revised: 03/03/2004] [Accepted: 03/15/2004] [Indexed: 11/17/2022] Open
Abstract
The severity of antigen-induced arthritis (AIA) is decreased in leptin-deficient ob/ob mice. However, joint inflammation in AIA depends on the immune response, which is impaired in ob/ob mice. In the present study we investigated the effects of leptin deficiency on zymosan-induced arthritis (ZIA), which is independent of adaptive immunity. Arthritis was induced by injection of zymosan into the knee joint. Joint swelling was similar after 6 and 24 hours in ob/ob and control mice. However, it remained elevated in ob/ob animals on day 3 whereas values normalized in controls. Histology revealed similar articular lesions in all animals on day 3, but on days 14 and 21 arthritis tended to be more severe in ob/ob mice. The acute phase response, reflected by circulating levels of IL-6 and serum amyloid A, was also more pronounced in ob/ob mice, although corticosterone was significantly elevated in these animals. Similar results were obtained in leptin receptor-deficient db/db mice. Thus, in contrast to AIA, ZIA is not impaired in leptin-deficient animals. On the contrary, resolution of acute inflammation appears to be delayed in the absence of leptin or leptin signalling, suggesting that chronic leptin deficiency interferes with adequate control of the inflammatory response in ZIA.
Collapse
|
20
|
Mykoniatis A, Anton PM, Wlk M, Wang CC, Ungsunan L, Blüher S, Venihaki M, Simeonidis S, Zacks J, Zhao D, Sougioultzis S, Karalis K, Mantzoros C, Pothoulakis C. Leptin mediates Clostridium difficile toxin A-induced enteritis in mice. Gastroenterology 2003; 124:683-91. [PMID: 12612907 DOI: 10.1053/gast.2003.50101] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Leptin regulates energy homeostasis and participates in the regulation of the hypothalamic-pituitary-adrenal axis. Although hyperleptinemia is described in experimental colitis, its role in the pathophysiology of enterotoxin-mediated diarrhea and inflammation remains unclear. We examined the role of leptin in the inflammatory diarrhea induced by toxin A from Clostridium difficile, the causative agent of antibiotic-related colitis. METHODS Toxin A (10 microg) or buffer were administered in ileal loops of leptin-deficient (ob/ob), leptin-resistant (db/db), or wild-type mice and enterotoxic responses were measured. RESULTS In toxin A-treated wild-type mice, circulating leptin and corticosterone levels were increased compared with buffer-injected animals. Toxin A also stimulated increased mucosal expression of the Ob-Rb at the messenger RNA (mRNA) and protein level. Ob/ob and db/db mice were partially protected against toxin A-induced intestinal secretion and inflammation, and this effect was reversed by leptin administration in ob/ob, but not db/db, mice. Basal- and toxin A-stimulated plasma corticosterone levels in ob/ob and db/db mice were higher compared with toxin A-treated wild-type mice. To assess whether the effect of leptin in intestinal inflammation is mediated by corticosteroids we performed adrenalectomy experiments in db/db and wild-type mice. Our results suggested that the diminished intestinal response to toxin A in db/db mice was related only in part to increased levels of corticosteroids. CONCLUSIONS Leptin plays an important role in regulating the severity of enterotoxin-mediated intestinal secretion and inflammation by activating both corticosteroid-dependent and -independent mechanisms.
Collapse
Affiliation(s)
- Andreas Mykoniatis
- Divisions of Gastroenterology and Endocrinology, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Inouye K, Shum K, Chan O, Mathoo J, Matthews SG, Vranic M. Effects of recurrent hyperinsulinemia with and without hypoglycemia on counterregulation in diabetic rats. Am J Physiol Endocrinol Metab 2002; 282:E1369-79. [PMID: 12006368 DOI: 10.1152/ajpendo.00480.2001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To understand the mechanisms whereby recurrent hypoglycemia increases the risk of subsequent hypoglycemia, it was necessary to differentiate the effects of recurrent hyperinsulinemia from those of hyperinsulinemic hypoglycemia. We examined basal and hypoglycemic endocrine function in normal rats, streptozotocin-diabetic controls, and diabetic rats exposed to 4 days of 2 episodes/day of hyperinsulinemic hypoglycemia (DH) or hyperinsulinemic hyperglycemia (DI). DH and DI rats differentiated the effects of hyperinsulinemia from those of hypoglycemia. In diabetic controls, basal plasma ACTH tended to be increased, and plasma corticosterone, plasma somatostatin, and pancreatic prosomatostatin and proglucagon mRNA were increased (P < 0.05) vs. normal rats. These parameters were normalized in DH and DI rats. In diabetic controls, glucagon, epinephrine, norepinephrine, corticosterone, and peak glucose production responses to hypoglycemia were reduced (P < 0.05) vs. normal rats. In DI rats, epinephrine responses were normalized. Conversely, DH rats displayed marked further impairment of epinephrine and glucose production responses and increased peripheral insulin sensitivity (P < 0.05 vs. diabetic controls). Both insulin regimens partially normalized glucagon and fully normalized norepinephrine and corticosterone responses. In summary, recurrent hyperinsulinemia in diabetic rats normalized most pituitary-adrenal, sympathoadrenal, and pancreatic parameters. However, concurrent hypoglycemia further impaired epinephrine and glucose production responses and increased insulin sensitivity. We conclude that 1) recurrent hypoglycemia may increase the risk of subsequent hypoglycemia by increasing insulin sensitivity, and 2) epinephrine counterregulation is particularly sensitive to impairment by recurrent hypoglycemia.
Collapse
Affiliation(s)
- Karen Inouye
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada, M5S 1A8
| | | | | | | | | | | |
Collapse
|
22
|
Small CJ, Kim MS, Stanley SA, Mitchell JR, Murphy K, Morgan DG, Ghatei MA, Bloom SR. Effects of chronic central nervous system administration of agouti-related protein in pair-fed animals. Diabetes 2001; 50:248-54. [PMID: 11272133 DOI: 10.2337/diabetes.50.2.248] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The melanocortin receptor (MC3-R and MC4-R) antagonist, agouti-related protein (AGRP), is a potent stimulant of food intake. We examined the effect of chronic intracerebroventricular (ICV) AGRP treatment on energy metabolism and pituitary function in ad libitum fed rats and rats administered AGRP and then pair-fed to a saline control group. Chronic ICV AGRP (83-132) administration (1 nmol/day for 7 days) significantly increased food intake and body weight in ad libitum fed animals compared with saline-treated controls (body weight on day 7: 272 +/- 6 [saline] vs. 319 +/- 8 g [AGRP ad libitum fed]; P < 0.001). A significant increase in the epididymal fat pad weight, interscapular brown adipose tissue (BAT) weight, and plasma leptin was also observed in the ad libitum fed group. In the AGRP pair-fed group, a significant increase in the epididymal fat pad weight, BAT weight, and plasma leptin was again observed, suggesting that AGRP caused metabolic changes independent of increased food intake. BAT uncoupling protein 1 (UCP-1) content was significantly decreased compared with saline controls in both the AGRP ad libitum fed (21 +/- 8% of saline control; P < 0.01) and AGRP pair-fed groups (24 +/- 7% of saline control; P < 0.01). Plasma thyroid-stimulating hormone (TSH) was significantly suppressed compared with saline controls in both the AGRP ad libitum fed and AGRP pair-fed groups (3.5 +/- 0.3 [saline] vs. 2.7 +/- 0.4 [AGRP ad libitum fed] vs. 2.1 +/- 0.2 ng/ml [AGRP pair-fed]; P < 0.01). This study demonstrates that independent of its orexigenic effects, chronic AGRP treatment decreased BAT UCP-1, suppressed plasma TSH, and increased fat mass and plasma leptin, suggesting that it may play a role in energy expenditure.
Collapse
Affiliation(s)
- C J Small
- Department of Metabolic Medicine, Imperial College School of Medicine, Hammersmith Hospital, London, UK
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Tallman DL, Taylor CG. Potential interactions of zinc in the neuroendocrine-endocrine disturbances of diabetes mellitus type 2. Can J Physiol Pharmacol 1999. [DOI: 10.1139/y99-111] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
An accumulation of evidence implicates leptin, insulin, glucocorticoids, proopiomelanocortin (POMC), and neuropeptide Y (NPY) interactions as being integral to metabolic control associated with neuroendocrine-endocrine functioning. Dysfunction of neuroendocrine-endocrine interactions contributes to the metabolic disturbances of diabetes mellitus type 2 (DM-2). Since Zn has a direct impact on the healthy functioning of hormonal and neuropeptide balance, it is possible that altered Zn status and metabolism in DM-2 are involved in some of the metabolic dysfunctions of DM-2.Key words: zinc, insulin, leptin, neuropeptide Y, glucocorticoids, proopiomelanocortin (POMC), diabetes, obesity.
Collapse
|
24
|
|
25
|
Miltenberger RJ, Mynatt RL, Wilkinson JE, Woychik RP. The role of the agouti gene in the yellow obese syndrome. J Nutr 1997; 127:1902S-1907S. [PMID: 9278579 DOI: 10.1093/jn/127.9.1902s] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The yellow obese syndrome in mice encompasses many pleiotropic effects including yellow fur, maturity-onset obesity, hyperinsulinemia, insulin resistance, hyperglycemia, increased skeletal length and lean body mass, and increased susceptibility to neoplasia. The molecular basis of this syndrome is beginning to be unraveled and may have implications for human obesity and diabetes. Normally, the agouti gene is expressed during the hair-growth cycle in the neonatal skin where it functions as a paracrine regulator of pigmentation. The secreted agouti protein antagonizes the binding of the alpha-melanocyte-stimulating hormone to its receptor (melanocortin 1 receptor) on the surface of hair bulb melanocytes, causing alterations in intracellular cAMP levels. Widespread, ectopic expression of the mouse agouti gene is central to the yellow obese phenotype, as demonstrated by the molecular cloning of several dominant agouti mutations and the ubiquitous expression of the wild-type agouti gene in transgenic mice. Recent experiments have revealed that the hypothalamus and adipose tissue are biologically active target sites for agouti in the yellow obese mutant lines.
Collapse
Affiliation(s)
- R J Miltenberger
- Mammalian Genetics and Development Section, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | | | | | | |
Collapse
|
26
|
Huszar D, Lynch CA, Fairchild-Huntress V, Dunmore JH, Fang Q, Berkemeier LR, Gu W, Kesterson RA, Boston BA, Cone RD, Smith FJ, Campfield LA, Burn P, Lee F. Targeted disruption of the melanocortin-4 receptor results in obesity in mice. Cell 1997; 88:131-41. [PMID: 9019399 DOI: 10.1016/s0092-8674(00)81865-6] [Citation(s) in RCA: 2155] [Impact Index Per Article: 79.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The melanocortin-4 receptor (MC4-R) is a G protein-coupled, seven-transmembrane receptor expressed in the brain. Inactivation of this receptor by gene targeting results in mice that develop a maturity onset obesity syndrome associated with hyperphagia, hyperinsulinemia, and hyperglycemia. This syndrome recapitulates several of the characteristic features of the agouti obesity syndrome, which results from ectopic expression of agouti protein, a pigmentation factor normally expressed in the skin. Our data identify a novel signaling pathway in the mouse for body weight regulation and support a model in which the primary mechanism by which agouti induces obesity is chronic antagonism of the MC4-R.
Collapse
Affiliation(s)
- D Huszar
- Millennium Pharmaceuticals, Inc., Cambridge, Massachusetts 02139, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Mellin TN, Cashen DE, Ronan JJ, Murphy BS, DiSalvo J, Thomas KA. Acidic fibroblast growth factor accelerates dermal wound healing in diabetic mice. J Invest Dermatol 1995; 104:850-5. [PMID: 7537778 DOI: 10.1111/1523-1747.ep12607026] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Acidic fibroblast growth factor (aFGF) is a potent mitogenic and chemotactic agent for vascular endothelial cells, dermal fibroblasts, and epidermal keratinocytes, the principal cellular constituents of skin. To explore its potential to heal chronic dermal wounds, we applied pure recombinant human aFGF topically to full-thickness excisional injuries in healing-impaired genetically diabetic mice. Transformation of the nonlinear percent initial wound areas as a function of time to linear rates of tissue ingrowth from the original wound edges showed that aFGF increased wound closure in a dose-dependent manner. Optimal 3-micrograms/cm2 doses of aFGF nearly tripled the linear rate of healing. The median time to complete closure decreased from 46 d in vehicle-treated wounds to only 16 d in those treated with aFGF. Histomorphometric analyses established that aFGF increased granulation tissue formation and reepithelialization throughout healing. Vehicle- and aFGF-treated wounds appeared to be histologically equivalent by the time of closure. Therefore, aFGF has potential therapeutic applications for promoting healing of dermal ulcers, especially in healing-impaired individuals.
Collapse
Affiliation(s)
- T N Mellin
- Department of Biochemistry, Merck Research Laboratories, Rahway, New Jersey, USA
| | | | | | | | | | | |
Collapse
|
28
|
Fitzpatrick F, Christeff N, Durant S, Dardenne M, Nunez EA, Homo-Delarche F. Glucocorticoids in the nonobese diabetic (NOD) mouse: basal serum levels, effect of endocrine manipulation and immobilization stress. Life Sci 1992; 50:1063-9. [PMID: 1552825 DOI: 10.1016/0024-3205(92)90102-u] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The NOD mouse is a recognized model for studying immunologically mediated insulin-dependent diabetes mellitus (IDDM). In most colonies, the disease appears with a greater preponderance in females than in males and castration alters the expression of the disease. The prevalence of diabetes may also vary depending upon environmental factors such as stress. Therefore, we measured in the NOD mouse serum glucocorticoid concentrations in basal and stress conditions. We observed in NOD as well as in C57BL/6 mice, taken as controls, a circadian rhythm of corticosterone, with females having higher values than males. After a single restraint stress, female and male NOD mice exhibit a comparable response, whereas after repeated stress, males respond significantly less than females, suggesting an adaptation phenomenon. In contrast, there is no difference in the pattern of corticosterone response of C57BL/6 females and males to both types of stress, but females always respond better than males. Moreover, whatever the stress considered, NOD mice generally exhibit a higher corticosterone response than C57BL/6 mice. The sexual dimorphism in diabetes expression in NOD mice may be related to the levels of corticosterone, a hyperglycemic hormone, in both basal and stress conditions. However, the understanding of corticosteroid effects in this model of type I IDDM is rather complex given their well known anti-inflammatory and immunosuppressive effects in other models of autoimmune diseases.
Collapse
|
29
|
Abstract
Mutations at more than 30 loci in mice have been shown to cause deleterious effects on the immune system. Immunologic defects caused by certain of these mutations are determined at the level of hematopoietic progenitor cells or at the level of hematopoietic cell-stromal cell interactions. The immunological mutants described in this paper serve as experimental tools with which to increase our understanding of the development and regulation of the mammalian immune system.
Collapse
Affiliation(s)
- L D Shultz
- Jackson Laboratory, Bar Harbor, Maine 04609
| |
Collapse
|
30
|
Homo-Delarche F, Fitzpatrick F, Christeff N, Nunez EA, Bach JF, Dardenne M. Sex steroids, glucocorticoids, stress and autoimmunity. J Steroid Biochem Mol Biol 1991; 40:619-37. [PMID: 1958562 DOI: 10.1016/0960-0760(91)90285-d] [Citation(s) in RCA: 181] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Interest in the field of neuroimmunoendocrinology is in full expansion. With regard to this, steroid influence on the immune system, in particular sex steroids and glucocorticoids, has been known for a long time. Sex steroids are part of the mechanism underlying the immune sexual dimorphism, as particularly emphasized in autoimmune diseases. Immunosuppressive and anti-inflammatory effects of glucocorticoids are now considered a physiological negative feedback loop to cytokines produced during an immune and/or inflammatory response. Psychosocial factors may play a role in the development of immunologically-mediated diseases, e.g. autoimmune diseases. The nonobese diabetic (NOD) mouse, that develops an immunologically-mediated insulin-dependent diabetes mellitus (IDDM) is an interesting model to study the role of endogenous steroids. Insulitis is present in both sexes, but diabetes has a strong preponderance in females. Hormonal alteration, such as castration, modulates the incidence of diabetes, whereas environmental factors, such as stress, accelerate the disease. In the present paper, we have reviewed the role of gender, sex steroid hormones, stress and glucocorticoids in autoimmunity as well as analyzed their different levels of actions and interrelationships, focusing particular attention on the immunologically-mediated IDDM of the NOD mouse.
Collapse
|
31
|
Dugail I, Quignard-Boulangé A, Le Liepvre X, Lavau M. Impairment of adipsin expression is secondary to the onset of obesity in db/db mice. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39902-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
32
|
Abstract
Recent studies have demonstrated a role for adrenal glucocorticoid hormones in the hyperphagia and obesity which follow lesions of the ventromedial hypothalamus (VMH). Although VMH lesions elevate morning plasma corticosterone levels, it is concluded that this contributes little to the development of obesity. More importantly, animals with VMH lesions appear to be hyperresponsive to very low levels of circulating glucocorticoids. The overeating and obesity are both prevented and reversed by either complete adrenalectomy or complete hypophysectomy (i.e., resulting in plasma corticosterone levels of less than 1.0 microgram/dl) and restored by dosages of glucocorticoids that have no effect on feeding behavior and weight gain in nonlesioned adrenalectomized animals. Mineralocorticoid hormones have no effect on hypothalamic obesity. Judging by the time course of effects on feeding behavior in VMH-damaged mice of a single intracerebroventricular injection of a low dose of glucocorticoid, which has no effect when administered intraperitoneally, it is concluded that glucocorticoids exert their effect centrally in a permissive, rather than a regulatory, manner. Stimulation of the neighboring paraventricular nuclei (PVN) with norepinephrine or neuropeptide Y produces a rapid feeding response which is also abolished by adrenalectomy and restored with administration of glucocorticoids. However, it is unlikely that the PVN is the site at which glucocorticoids exert their effect in animals with VMH lesions, for PVN lesions or knife-cuts, or combination VMH-PVN lesions, also result in hyperphagia and obesity. It is concluded that adrenal glucocorticoid hormones exert their permissive effects on feeding behavior at brain sites other than the medial hypothalamus. The septo-hippocampal complex is suggested as a possible site.
Collapse
Affiliation(s)
- B M King
- Department of Psychology, University of New Orleans, LA 70148
| |
Collapse
|
33
|
Shargill NS, Tatoyan A, Fukushima M, Antwi D, Bray GA, Chan TM. Effect of ciglitazone on glucose uptake and insulin sensitivity in skeletal muscle of the obese (ob/ob) mouse: distinct insulin and glucocorticoid effects. Metabolism 1986; 35:64-70. [PMID: 3510364 DOI: 10.1016/0026-0495(86)90097-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The oral hypoglycemic agent, ciglitazone, (5-[4-(1-methylcyclohexylmethoxy)benzyl]-thiazolidine-2,4-dione), was fed for nine days to genetically obese (ob/ob) mice aged 5 to 6 weeks. This treatment resulted in a lowering of plasma glucose and circulating insulin levels, but did not cause a fall in plasma corticosterone levels. Basal 2-deoxy-D-glucose uptake by the perfused hindquarters of ob/ob mice was unchanged by ciglitazone feeding. In the presence of 0.1 mU/mL insulin in the perfusion medium, there was a significant increase in the uptake rate of 2-deoxy-D-glucose by the skeletal muscle of ciglitazone-treated ob/ob mice, while there was no insulin effect in untreated ob/ob mice. Insulin at a concentration of 1 mU/mL caused a further stimulation of 2-deoxy-D-glucose transport. However, this response was significantly lower than the maximal stimulation in lean mice. Ciglitazone feeding did not have any effect on [5-3H]-glucose metabolism by the perfused muscle which remained subnormal, suggesting that the posttransport metabolism of glucose was limited by substrate availability. In the perfused mouse liver, net [14C]-glucose production from [14C]-lactate was unchanged by ciglitazone treatment while gluconeogenesis from [14C]-alanine was reduced. These findings show that ciglitazone produces its hypoglycemic effect by improving the insulin sensitivity in skeletal muscle, as others have reported in the adipose tissue. The presence of elevated plasma levels of corticosterone and lower levels of insulin in ciglitazone-treated ob/ob mice suggests that the adrenal glucocorticoids are responsible for the basal defects in glucose transport and the hyperinsulinemia is responsible for the insulin insensitivity.
Collapse
|
34
|
Gonzalez C, Jolin T. Effect of streptozotocin diabetes and insulin replacement on growth hormone in rats. J Endocrinol Invest 1985; 8:7-11. [PMID: 3886772 DOI: 10.1007/bf03350625] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The effects of insulin deprivation on the growth rate, plasma and pituitary growth hormone (GH) and GH synthesis were investigated in male Wistar rats. Diabetes was induced by administration of streptozotocin (STZ), 7 mg/100 g bw, and plasma and pituitary GH levels were measured by means of a specific radioimmunoassay. GH synthesis was determined in pituitaries by the in vitro incorporation of [3H] leucine into specific immunoprecipitates. The body weight and the pituitary GH content of normally developing rats showed an almost linear increase throughout the observation period, whereas diabetic rats stopped growing immediately after receiving STZ, and remained smaller than age-paired controls. Pituitary GH content remained within the control range through the 5 days following STZ administration and thereafter decreased reaching 10% of control values by the 30th day. Furthermore, pituitaries from diabetic rats incorporated [3H] leucine into r-GH at a greatly reduced rate, which could explain the diminished r-GH storage in pituitaries of diabetic rats. Plasma GH concentrations remained within the normal range for 10 days after STZ, thereafter plasma GH were markedly reduced. Insulin treatment prevented the metabolic changes, and restored normal levels of plasma and pituitary GH in diabetic rats. These findings indicate that diabetes, in rat, is characterized by an inhibitory effect on GH secretion, probably via a diminished GH synthesis by the pituitary gland.
Collapse
|
35
|
Stenling R, Hägg E, Falkmer S. Stereological studies on the rat small intestinal epithelium. III. Effects of short-term alloxan diabetes. VIRCHOWS ARCHIV. B, CELL PATHOLOGY INCLUDING MOLECULAR PATHOLOGY 1984; 47:263-70. [PMID: 6151307 DOI: 10.1007/bf02890209] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Short-term experimental diabetes was used to explore the effect of hyperplastic adaption of the small intestine mucosa on the structure of its absorptive cells. Diabetes was induced in adult female rats by intravenous alloxan administration under kidney protection; similar rats, injected with physiological saline, served as controls. Quantitative light microscopy, performed after 1 month of diabetes, revealed structural changes in the jejunal mucosa consistent with hyperplasia. These changes comprised increased height of the villi (31%) and increased depth of the crypts (34%) in comparison with the control rats. At the electron microscopical level, stereological measurements of the jejunal absorptive cells revealed a decrease in their apical surface area, both for the apical surface density (24%) and for the enlargement factor due to the microvilli (12%). In the duodenal mucosa, this kind of experimental diabetes did not induce any significant light microscopical or electron microscopical changes of the villi, the crypts, or the absorptive cells. It was concluded that the adaptive capacity of the structure of the small intestine mucosa to short term experimental diabetes is more pronounced in the jejunum than in the duodenum, and that the adaptive response also includes alterations in the structure of the absorptive cells.
Collapse
|
36
|
Ohshima K, Shargill NS, Chan TM, Bray GA. Adrenalectomy reverses insulin resistance in muscle from obese (ob/ob) mice. THE AMERICAN JOURNAL OF PHYSIOLOGY 1984; 246:E193-7. [PMID: 6421176 DOI: 10.1152/ajpendo.1984.246.2.e193] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Glucose transport and insulin resistance in the skeletal muscle of the genetically obese (ob/ob) mouse has been studied in animals at 6-7 wk of age using an in situ perfused hindquarter preparation. Rates of glucose uptake and the uptake of radioactively labeled 2-deoxy-D-glucose were lower in muscles from intact ob/ob mice than in those from their lean littermates. Following adrenalectomy the basal rate of glucose or 2-deoxy-D-glucose uptake in the ob/ob mice was restored to normal. The uptake of 2-deoxyglucose was tested at two insulin concentrations. In lean mice, adrenalectomy had no effect on 2-deoxyglucose uptake. Adrenalectomy, however, restored the responsiveness to insulin in the ob/ob mouse to normal. The activity ratio of muscle glycogen synthase was elevated by insulin but the effect was greater in the lean animals with or without adrenal glands than in the obese mouse. Adrenalectomy in the obese mouse did not correct this defect.
Collapse
|
37
|
Gebhard RL, Levine AS, Prigge WF, Brown DM, Handwerger BS, Morley JE. Hepatic and intestinal 3-hydroxy-3-methylglutaryl coenzyme A reductase activity in genetically diabetic mice. Biochem Biophys Res Commun 1983; 113:638-44. [PMID: 6870877 DOI: 10.1016/0006-291x(83)91774-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cholesterol synthesis rate, as determined by 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, is characterized in the major organs of genetically diabetic mice. Both C57BL/Ks db+/db+ and C57BL/6 ob+/ob+ mice are hyperinsulinemic and insulin-resistant. These animals demonstrate loss of the circadian rhythm of hepatic reductase activity and a tendency for increased intestinal activity. As a result, proportionally more endogenous cholesterol synthesis occurs in intestinal mucosa than liver in genetically diabetic animals. Thus, the alterations in activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase which are observed in animal models of diabetes are the result of diminished insulin effect rather than insulin level.
Collapse
|
38
|
Carson KA, Hanker JS, Kirshner N. The adrenal medulla of the diabetic mouse (C57BL/KsJ, db/db): biochemical and morphological changes. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A, COMPARATIVE PHYSIOLOGY 1982; 72:279-85. [PMID: 6125301 DOI: 10.1016/0300-9629(82)90220-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
1. Anatomic and biochemical indices of adrenal medullary function were studied in mice (Mus musculus) with hereditary mellitus (C57BL/KsJ, db/db). 2. In the diabetic mice increases in medullary catecholamine content and in the activities of tyrosine hydroxylase, dopamine-beta-hydroxylase, and phenylethanolamine-N-methyltransferase were accompanied by increases in adrenal weight and size. 3. Morphometric study of adrenals from diabetic mice showed that the medulla was increased in size but had a lower cell density indicating that medullary hypertrophy as well as hyperplasia were probably responsible for this size increase. 4. These observations are consistent with the occurrence of chronic adrenal medullary stimulation in the diabetic syndrome of these mice.
Collapse
|
39
|
Leiter EH, Bedigian HG. Intracisternal A-particles in genetically diabetic mice: identification in pancreas and induction in cultured beta cells. Diabetologia 1979; 17:175-85. [PMID: 229051 DOI: 10.1007/bf01219746] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Sucrose density gradient analysis of purified pancreatic homogenates from glycaemic C57BL/Ks diabetes (db/db) mice and their normoglycaemic controls have revealed the presence in the diabetics of increased Mg++-dependent RNA-directed DNA polymerase activity sedimenting with a density of approximately 1.21 g/cm3. Electron microscopy revealed that this fraction contained typical intracisternal A-particles. Purified cultures of pancreatic islet cells 4--7 day old postnatal "misty diabetic" mice and normal siblings were established and then maintained in Eagle's minimal essential medium without serum. Under these conditions, the presence of intracisternal A-particles in beta cells of both mutant and control genotypes was very rare. No change in numbers of intracisternal A-particles was seen after 2--4 days of incubation in Dulbecco's-modified minimal essential medium containing 5.5 mmol/l glucose. However, when the glucose concentration of Dulbecco's medium was elevated to 16.5 mmol/l, ultrastructural changes specific to the beta cell population occurred that were reminiscent of those alterations observed in situ. Intracisternal A-particles were commonly seen in cultured beta cells showing hypersecretion-stress morphology. Since equal numbers of intracisternal A-particles were present in cultured beta cells from normal and mutant mice, it was concluded that the db gene itself was not required for intracisternal A-particle expression. The cell culture results suggest that elevated intracisternal A-particle activity observed in vivo may be produced directly or indirectly by the ambient high blood glucose levels characteristic of this mutant.
Collapse
|
40
|
Appel MC, Schibly BA, Kamara JA, Sorenson RL. Adrenal gland involvement in mice with hereditary obesity and diabetes mellitus. Morphological studies. Diabetologia 1979; 16:391-8. [PMID: 467849 DOI: 10.1007/bf01223160] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The contribution of the adrenal gland to the development of the spontaneous syndrome of obesity and diabetes in Yellow-KK (Y-KK) mice was studied. Six-month old Y-KK mice exhibited hyperadrenocorticism and adrenal cortex enlargement. Light microscopic morphometric studies of Y-KK adrenals revealed an expanded volume of the adrenal cortex resulting from hyperplasia of zona fasciculata and reticularis cells. Ultrastructural studies revealed fewer lipid droplets, increased numbers of mitochondria and a more extensively developed Golgi system with zona fasciculata and reticularis cells. This cytological evidence of enhanced steroid biosynthetic and secretory activity was consistent with increased levels of plasma immunoreactive corticosterone. Structural and functional abnormalities of Y-KK adrenals were preceded by the development of obesity, hyperglycaemia and hyperinsulinaemia. It is unlikely, therefore, that the adrenal plays a casual role in the syndrome's pathogenesis, although, hyperadrenocorticism may be in part responsible for an exacerbation of the observed phenomena.
Collapse
|
41
|
Gärtner K. Glomerular hyperfiltration during the onset of diabetes mellitus in two strains of diabetic mice (c57bl/6j db/db and c57bl/ksj db/db). Diabetologia 1978; 15:59-63. [PMID: 98379 DOI: 10.1007/bf01219330] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
42
|
Mahmood A, Pathak RM, Agarwal N. Effect of chronic alloxan diabetes and insulin administration on intestinal brush border enzymes. EXPERIENTIA 1978; 34:741-2. [PMID: 149019 DOI: 10.1007/bf01947295] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Brush border sucrase and lactase activities are significantly elevated in alloxan-induced chronic diabetes and are restored to control levels after insulin treatment. Alkaline phosphatase and Mg-ATPase levels remain unchanged in diabetes, compared to a control group. Insulin treatment alone to control animals also led to enhanced activities of these enzymes.
Collapse
|