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Yang X, Xu Z, Zhang C, Cai Z, Zhang J. Metformin, beyond an insulin sensitizer, targeting heart and pancreatic β cells. Biochim Biophys Acta Mol Basis Dis 2016; 1863:1984-1990. [PMID: 27702625 DOI: 10.1016/j.bbadis.2016.09.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/17/2016] [Accepted: 09/27/2016] [Indexed: 12/22/2022]
Abstract
Metformin, a biguanide derivate, is known as the first-line antidiabetic agent for type 2 diabetes mellitus (T2DM) treatment. It reduces insulin resistance and decreases blood glucose concentration by inhibiting gluconeogenesis and suppressing hepatic glucose production with improved peripheral tissue insulin sensitivity. As an insulin sensitizer, metformin takes pleiotropic actions and exerts protective effects on multiple organs mainly in insulin-targeted tissues such as liver, muscle, and adipose tissues. Recent studies discover that metformin also plays essential roles in heart and pancreatic β cells - two important organs in metabolic regulation. Metformin not only protects T2DM patients from cardiovascular diseases and heart failure, but also restores insulin secretion activities and protects pancreatic β cells from lipotoxicity or glucotoxicity. Although accumulated evidence shed light on the metformin action, the precise mechanism of metformin is still under investigation. Further laboratory investigations and clinical trials are needed to pinpoint a map of metformin action. Based on recent findings, this review characterizes the beneficial role of metformin in cardiovascular diseases and pancreatic β cells.
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Affiliation(s)
- Xin Yang
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China; Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, National Clinical Research Center for Metabolic Diseases, Central South University, Changsha, Hunan 410011, China
| | - Zhipeng Xu
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China; Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, National Clinical Research Center for Metabolic Diseases, Central South University, Changsha, Hunan 410011, China
| | - Chunlan Zhang
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China; Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, National Clinical Research Center for Metabolic Diseases, Central South University, Changsha, Hunan 410011, China
| | - Zixin Cai
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China; Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, National Clinical Research Center for Metabolic Diseases, Central South University, Changsha, Hunan 410011, China
| | - Jingjing Zhang
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China; Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, National Clinical Research Center for Metabolic Diseases, Central South University, Changsha, Hunan 410011, China.
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Li L, Xu M, Shen B, Li M, Gao Q, Wei SG. Moderate exercise prevents neurodegeneration in D-galactose-induced aging mice. Neural Regen Res 2016; 11:807-15. [PMID: 27335566 PMCID: PMC4904473 DOI: 10.4103/1673-5374.182709] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
D-galactose has been widely used in aging research because of its efficacy in inducing senescence and accelerating aging in animal models. The present study investigated the benefits of exercise for preventing neurodegeneration, such as synaptic plasticity, spatial learning and memory abilities, in mouse models of aging. D-galactose-induced aging mice were administered daily subcutaneous injections of D-galactose at the base of the neck for 10 consecutive weeks. Then, the mice were subjected to exercise training by running on a treadmill for 6 days a week. Shortened escape latency in a Morris water maze test indicated that exercise improved learning and memory in aging mice. The ameliorative changes were likely induced by an upregulation of Bcl-2 and brain-derived neurotrophic factor, the repression of apoptosis factors such as Fas and Bax, and an increase in the activity of glucose transporters-1 and 4. The data suggest moderate exercise may retard or inhibit neurodegeneration in D-galactose-induced aging mice.
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Affiliation(s)
- Li Li
- Department of Infectious Medicine, Beijing YouAn Hospital Affiliated to Capital Medical University, Beijing, China
| | - Meng Xu
- Department of Infectious Medicine, Beijing YouAn Hospital Affiliated to Capital Medical University, Beijing, China
| | - Bo Shen
- Department of Infectious Medicine, Beijing YouAn Hospital Affiliated to Capital Medical University, Beijing, China
| | - Man Li
- Department of Children's and Women's Health, School of Public Health, Capital Medical University, Beijing, China
| | - Qian Gao
- Department of Children's and Women's Health, School of Public Health, Capital Medical University, Beijing, China
| | - Shou-Gang Wei
- Department of Children's and Women's Health, School of Public Health, Capital Medical University, Beijing, China
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Farese RV, Lee MC, Sajan MP. Atypical PKC: a target for treating insulin-resistant disorders of obesity, the metabolic syndrome and type 2 diabetes mellitus. Expert Opin Ther Targets 2015; 18:1163-75. [PMID: 25213731 DOI: 10.1517/14728222.2014.944897] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION The prevalence of obesity, the metabolic syndrome and type 2 diabetes mellitus have reached pandemic levels. Present therapies do not directly target the key factor responsible for the insulin resistance that underlies the development of these syndromes. AREAS COVERED This review focuses on hepatic atypical PKC (aPKC) as a key target for treating these disorders. It reviews data obtained from multiple experimental mouse models of obesity and type 2 diabetes, and hepatocytes of type 2 diabetic humans. EXPERT OPINION The review shows that hepatic aPKC is excessively activated by diet-derived lipids and by insulin itself in hyperinsulinemic states. It also shows how excessively activated hepatic aPKC increases expression of gluconeogenic, lipogenic and proinflammatory factors that underlie the development of glucose intolerance, insulin resistance, obesity, hepatosteatosis and hyperlipidemia. Most importantly, the review shows how the selective inhibition of hepatic aPKC by a variety of means, including expression of inhibitory forms of aPKC, genetic deletion of aPKC and use of several newly developed small-molecular-weight chemical agents result in correction of hepatic abnormalities, such as excessive expression of gluconeogenic, lipogenic and proinflammatory factors, and correction or improvement in clinical abnormalities (glucose intolerance, obesity, hepatosteatosis and hyperlipidemia).
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Shen KP, Hao CL, Yen HW, Chen CY, Wu BN, Lin HL. Pre-germinated brown rice prevents high-fat diet induced hyperglycemia through elevated insulin secretion and glucose metabolism pathway in C57BL/6J strain mice. J Clin Biochem Nutr 2014; 56:28-34. [PMID: 25834303 PMCID: PMC4306661 DOI: 10.3164/jcbn.14-50] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2014] [Accepted: 08/03/2014] [Indexed: 12/27/2022] Open
Abstract
This study investigated the effect and mechanism of pre-germinated brown rice (PGBR) prevented hyperglycemia in C57BL/6J mice fed high-fat-diet (HFD). Normal six-week-old mice were randomly divided into three groups. Group 1 was fed standard-regular-diet (SRD) and group 2 was fed HFD for 16 weeks. In group 3, the mice were fed a HFD with its carbohydrate replaced with PGBR for 16 weeks. Comparing the SRD and HFD groups, we found the HFD group had higher blood pressure, higher concentrations of blood glucose and HbA1c. The HFD group had less protein expression of insulin receptor (IR), insulin receptor substrate-1 (IRS-1), phosphatidylinositol-3-kinase (PI3K), glucose transporter-4 (GLUT-4) and glucokinase (GCK) and greater expression of glucogen synthase kinase (GSK) in skeletal muscle. The HFD group also had less expression of IR, serine/threonine kinase PI3K-linked protein kinase B (Akt/PKB), AMP-activated protein kinase (AMPK), GCK and peroxisome proliferator-activated receptor γ (PPARγ) in liver. In the HFD + PGBR group, the PGBR could reverse the disorders of blood pressure, blood glucose, HbA1c and increase insulin concentration. PGBR increased the IR, IRS-1, PI3K, Akt, GLUT-1 and GLUT-4 proteins, and ameliorated AMPK, GCK, GSK and PPARγ proteins. Together, PGBR prevented HFD-induced hyperglycemia through improving insulin levels, insulin receptor, glucose transporters and enhancing glucose metabolism.
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Affiliation(s)
- Kuo-Ping Shen
- Department of Nursing, Meiho University, 23 Ping-Kuang Road, Neipu, Pingtung 91202, Taiwan
| | - Chi-Long Hao
- Division of Cardiology, Department of Internal Medicine, Pingtung Christian Hospital, 60 Da-Lian Road, Pingtung 90059, Taiwan
| | - Hsueh-Wei Yen
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, 100 Shin-Chuan 1st Road, Kaohsiung 807, Taiwan
| | - Chun-Yen Chen
- MS program for Applied Health and Biotechnology, Meiho University, 23 Ping-Kuang Road, Neipu, Pingtung 91202, Taiwan
| | - Bin-Nan Wu
- Department of Pharmacology, School of Medicine, College of Medicine, Kaohsiung Medical University, 100 Shin-Chuan 1st Road, Kaohsiung 807, Taiwan
| | - Hui-Li Lin
- Department of Food Science and Nutrition, Meiho University, 23 Ping-Kuang Road, Neipu, Pingtung 91202, Taiwan
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Christensen M, Miossec P, Larsen BD, Werner U, Knop FK. The design and discovery of lixisenatide for the treatment of type 2 diabetes mellitus. Expert Opin Drug Discov 2014; 9:1223-51. [DOI: 10.1517/17460441.2014.942638] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Abstract
In healthy humans, the incretin glucagon-like peptide 1 (GLP-1) is secreted after eating and lowers glucose concentrations by augmenting insulin secretion and suppressing glucagon release. Additional effects of GLP-1 include retardation of gastric emptying, suppression of appetite and, potentially, inhibition of β-cell apoptosis. Native GLP-1 is degraded within ~2-3 min in the circulation; various GLP-1 receptor agonists have, therefore, been developed to provide prolonged in vivo actions. These GLP-1 receptor agonists can be categorized as either short-acting compounds, which provide short-lived receptor activation (such as exenatide and lixisenatide) or as long-acting compounds (for example albiglutide, dulaglutide, exenatide long-acting release, and liraglutide), which activate the GLP-1 receptor continuously at their recommended dose. The pharmacokinetic differences between these drugs lead to important differences in their pharmacodynamic profiles. The short-acting GLP-1 receptor agonists primarily lower postprandial blood glucose levels through inhibition of gastric emptying, whereas the long-acting compounds have a stronger effect on fasting glucose levels, which is mediated predominantly through their insulinotropic and glucagonostatic actions. The adverse effect profiles of these compounds also differ. The individual properties of the various GLP-1 receptor agonists might enable incretin-based treatment of type 2 diabetes mellitus to be tailored to the needs of each patient.
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Affiliation(s)
- Juris J Meier
- Division of Diabetology, St Josef-Hospital, Ruhr-University Bochum, Gudrunstraße 56, 44791 Bochum, Germany.
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Abstract
PURPOSE OF REVIEW To review the aberrations of insulin signaling to atypical protein kinase C (aPKC) in muscle and liver that generate cardiovascular risk factors, including obesity, hypertriglyceridemia, hypercholesterolemia, insulin resistance and glucose intolerance in type 2 diabetes mellitus (T2DM), and obesity-associated metabolic syndrome (MetSyn). RECENT FINDINGS aPKC and Akt mediate the insulin effects on glucose transport in muscle and synthesis of lipids, cytokines and glucose in liver. In T2DM, whereas Akt and aPKC activation are diminished in muscle, and hepatic Akt activation is diminished, hepatic aPKC activation is conserved. Imbalance between muscle and hepatic aPKC activation (and expression of PKC-ι in humans) by insulin results from differential downregulation of insulin receptor substrates that control phosphatidylinositol-3-kinase. Conserved activation of hepatic aPKC in hyperinsulinemic states of T2DM, obesity and MetSyn is problematic, as excessive activation of aPKC-dependent lipogenic, gluconeogenic and proinflammatory pathways increases the cardiovascular risk factors. Indeed, selective inhibition of hepatic aPKC by adenoviral-mediated expression of kinase-inactive aPKC, or newly developed small-molecule biochemicals, dramatically improves abdominal obesity, hepatosteatosis, hypertriglyceridemia, hypercholesterolemia, insulin resistance and glucose intolerance in murine models of obesity and T2DM. SUMMARY Hepatic aPKC is a unifying target for treating multiple clinical abnormalities that increase the cardiovascular risk in insulin-resistant states of obesity, MetSyn and T2DM.
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Affiliation(s)
- Robert V Farese
- Medical and Research Services, James A. Haley Veterans Medical Center Department of Internal Medicine, University of South Florida College of Medicine, Tampa Metabolism Division, Roskamp Institute, Sarasota, Florida, USA
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Yang LPH. Saxagliptin: a review of its use as combination therapy in the management of type 2 diabetes mellitus in the EU. Drugs 2012; 72:229-48. [PMID: 22221000 DOI: 10.2165/11208160-000000000-00000] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Saxagliptin (Onglyza™) is a dipeptidyl peptidase 4 inhibitor widely approved for the treatment of type 2 diabetes mellitus. In the EU, saxagliptin is indicated as combination therapy with metformin, a sulfonylurea, a thiazolidinedione, or insulin (with or without metformin) for the treatment of adult patients with type 2 diabetes, including those with mild to severe renal impairment. This article reviews the clinical efficacy and tolerability of add-on saxagliptin therapy in patients with type 2 diabetes, in line with its approved indications in the EU, and summarizes the drug's pharmacological properties. The clinical efficacy of saxagliptin 5 mg/day in combination with metformin, glibenclamide (glyburide), a thiazolidinedione, or insulin (with or without metformin) has been demonstrated in several randomized, double-blind, placebo-controlled, multicentre, phase III trials (18-104 weeks in duration) in patients with type 2 diabetes. In these trials, glycosylated haemoglobin (HbA(1c)) was changed from baseline (primary endpoint) by a greater extent with add-on saxagliptin 5 mg/day (-1.09% to +0.03%) than with comparator regimens (-0.44% to +0.69%). Two other randomized, double-blind trials showed that saxagliptin 5 mg/day as add-on therapy to metformin was noninferior to uptitrated glipizide in terms of lowering HbA(1c) (-0.74% vs -0.80%) at 52 weeks, or sitagliptin (-0.52% vs -0.62%) at 18 weeks. Saxagliptin 2.5 mg/day as add-on to existing anti-diabetic therapy was also effective for up to 52 weeks in a randomized, double-blind, placebo-controlled, multicentre trial in patients with type 2 diabetes and renal impairment (HbA(1c) was reduced by 1.08% vs 0.36%; p ≤ 0.007). Saxagliptin as add-on therapy for up to 4 years was generally well tolerated in clinical trials. Treatment with saxagliptin did not increase the risk of hypoglycaemia or cardiovascular outcomes relative to placebo or active comparators, and was generally weight neutral. In conclusion, saxagliptin is a useful option as add-on therapy to metformin, a sulfonylurea, a thiazolidinedione, or insulin (with or without metformin) in patients with type 2 diabetes who require combination therapy.
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Affiliation(s)
- Lily P H Yang
- Adis, a Wolters Kluwer Business, Auckland, New Zealand.
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Brown MT, LeRoith D. Overcoming challenges in Type 2 diabetes management to improve patient outcomes. Expert Rev Endocrinol Metab 2010; 5:741-751. [PMID: 30764026 DOI: 10.1586/eem.10.45] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
As obesity and Type 2 diabetes mellitus reach epidemic proportions worldwide, glycemic control and prevention of complications have become even more critical. We searched studies published between January 2006 and January 2010 to identify and discuss the challenges facing healthcare professionals and patients in reaching glycemic targets. MEDLINE and Derwent Drug File searches were conducted with the following search terms: Type 2 diabetes mellitus, medication adherence, antihyperglycemic agents, glucose control, and clinical inertia. In this article we will outline the commonly used medications and present the advantages and disadvantages of each class of drug. Additionally, we will present the dipeptidyl peptidase-4 inhibitors and their place in the treatment of patients with Type 2 diabetes mellitus.
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Affiliation(s)
- Marie T Brown
- a Department of Internal Medicine, Rush University Medical Center, 6326 West Roosevelt Road, Oak Park, IL 60304, USA.
| | - Derek LeRoith
- b Division of Endocrinology, Diabetes & Bone Diseases, Mount Sinai School of Medicine, NY, USA
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Jeong I, Patel AY, Zhang Z, Patil PB, Nadella ST, Nair S, Ralston L, Hoormann JK, Fisher JS. Role of ataxia telangiectasia mutated in insulin signalling of muscle-derived cell lines and mouse soleus. Acta Physiol (Oxf) 2010; 198:465-75. [PMID: 20003097 DOI: 10.1111/j.1748-1716.2009.02069.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIM Ataxia telangiectasia mutated (ATM) reportedly plays a role in insulin-stimulated activation of Akt in some cell types but not in others. The role of ATM in insulin signalling has not been firmly resolved for skeletal muscle cells, for which Akt phosphorylation is a pivotal step in stimulation of glucose transport. Accordingly, our aim was to determine the role of ATM in insulin effects for cell lines derived from skeletal muscle and for skeletal muscle. METHODS We examined insulin effects in L6 myotubes, mouse soleus, C2C12 myotubes and differentiated rhabdomyosarcoma (RD) cells in the presence and absence of a low concentration (1 microm) of the ATM inhibitor KU55933. We also compared insulin signalling in C2C12 cells expressing shRNA against ATM and control cell lines (empty vector; cells expressing non-targeting shRNA). RESULTS In L6 myotubes and mouse soleus muscle, KU55933 inhibited insulin-stimulated phosphorylation of the 160 kDa substrate of Akt (AS160) despite no effect on Akt. In contrast, KU55933 prevented insulin-stimulated Akt phosphorylation in C2C12 myotubes. Furthermore, C2C12 myotubes expressing shRNA against ATM displayed reduced insulin-stimulated Akt phosphorylation compared to controls. KU55933 also decreased insulin-stimulated Akt phosphorylation in differentiated RD cells. CONCLUSION These model-dependent differences in the role of ATM in insulin action demonstrate a role of ATM in insulin-stimulated phosphorylation of Akt (in C2C12 and RD cells) but also allow the elucidation of a novel, Akt-independent role of ATM (in L6 myotubes and mouse soleus, at the level of AS160) in insulin signalling.
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Affiliation(s)
- I Jeong
- Department of Biology, Saint Louis University, MO 63103, USA
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Current world literature. Curr Opin Lipidol 2009; 20:512-9. [PMID: 19935200 DOI: 10.1097/mol.0b013e328334096a] [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: 12/24/2022]
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Current literature in diabetes. Diabetes Metab Res Rev 2009; 25:i-xii. [PMID: 19405078 DOI: 10.1002/dmrr.973] [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: 11/06/2022]
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Winkler G, Cseh K. Molecular mechanisms of insulin resistance in obesity and type 2 diabetes mellitus. Orv Hetil 2009; 150:771-80. [DOI: 10.1556/oh.2009.28608] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A zsírszövetben az inzulinreceptor jelátviteli folyamatait auto-, para- és endokrin hatásokkal szabályozó számos fehérje termelődik és szekretálódik. Ezek közül több, így a tumornekrózis-faktor-α és szolúbilis receptor formái, az sTNFR1 és sTNFR2, a rezisztin, retinolkötő fehérje-4, plazminogénaktivátor-inhibitor, lipokain-1 gátolja az inzulin jelátviteli folyamatait és inzulinrezisztenciát okoz, elsősorban a zsírszövetben, a májban, az izomszövetben, az agyban, az endothelsejtekben, valamint a hasnyálmirigy β-sejtjeiben. Más fehérjék, így az adiponektin, visfatin, vaspin, omentin, apelin és chemerin pedig javítják az inzulinreceptor jelátvitelét. Az összefoglalás áttekinti az inzulinreceptor jelátviteli folyamatainak főbb részleteit és kitér az elhízásban, valamint a 2-es típusú cukorbetegségben észlelhető inzulin- és citokinrezisztenciák patomechanizmusában a közelmúltban megismert molekuláris tényezőkre (például a suppressor of cytokine signaling fehérje család).
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Affiliation(s)
- Gábor Winkler
- 1 Fővárosi Önkormányzat Szent János Kórház és Észak-budai Egyesített Intézményei II. Belgyógyászati Osztály Budapest
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