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Viegas I, Di Nunzio G, Belew GD, Torres AN, Silva JG, Perpétuo L, Barosa C, Tavares LC, Jones JG. Integration of Liver Glycogen and Triglyceride NMR Isotopomer Analyses Provides a Comprehensive Coverage of Hepatic Glucose and Fructose Metabolism. Metabolites 2022; 12:1142. [PMID: 36422282 PMCID: PMC9698123 DOI: 10.3390/metabo12111142] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/10/2022] [Accepted: 11/16/2022] [Indexed: 10/18/2023] Open
Abstract
Dietary glucose and fructose are both efficiently assimilated by the liver but a comprehensive measurement of this process starting from their conversion to sugar phosphates, involvement of the pentose phosphate pathway (PPP), and conversion to glycogen and lipid storage products, remains incomplete. Mice were fed a chow diet supplemented with 35 g/100 mL drinking water of a 55/45 fructose/glucose mixture for 18 weeks. On the final night, the sugar mixture was enriched with either [U-13C]glucose or [U-13C]fructose, and deuterated water (2H2O) was also administered. 13C-isotopomers representing newly synthesized hepatic glucose-6-phosphate (glucose-6-P), glycerol-3-phosphate, and lipogenic acetyl-CoA were quantified by 2H and 13C NMR analysis of post-mortem liver glycogen and triglyceride. These data were applied to a metabolic model covering glucose-6-P, PPP, triose-P, and de novo lipogenesis (DNL) fluxes. The glucose supplement was converted to glucose-6-P via the direct pathway, while the fructose supplement was metabolized by the liver to gluconeogenic triose-P via fructokinase-aldolase-triokinase. Glucose-6-P from all carbohydrate sources accounted for 40-60% of lipogenic acetyl-CoA and 10-12% was oxidized by the pentose phosphate pathway (PPP). The yield of NADPH from PPP flux accounted for a minority (~30%) of the total DNL requirement. In conclusion, this approach integrates measurements of glucose-6-P, PPP, and DNL fluxes to provide a holistic and informative assessment of hepatic glucose and fructose metabolism.
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Affiliation(s)
- Ivan Viegas
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Giada Di Nunzio
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
| | - Getachew D. Belew
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
- Biotechnology Department, Addis Ababa Science and Technology University, Addis Ababa, Ethiopia
| | - Alejandra N. Torres
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
| | - João G. Silva
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
| | - Luis Perpétuo
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
- iBiMED, Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Cristina Barosa
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
| | - Ludgero C. Tavares
- CIVG—Vasco da Gama Research Center, University School Vasco da Gama—EUVG, 3020-210 Coimbra, Portugal
| | - John G. Jones
- Center for Neurosciences and Cell Biology, University of Coimbra, UC-Biotech, Biocant Park, Nucleo 8, Lote 4, 3060-197 Cantanhede, Portugal
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2
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Belew GD, Jones JG. De novo lipogenesis in non-alcoholic fatty liver disease: Quantification with stable isotope tracers. Eur J Clin Invest 2022; 52:e13733. [PMID: 34927251 DOI: 10.1111/eci.13733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/11/2021] [Accepted: 12/13/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND Non-alcoholic fatty liver disease (NAFLD) is characterized as an abnormal accumulation of triglyceride in hepatocytes. Hepatic de novo lipogenesis may play an important role in the accumulation of lipids in the liver during NAFLD. Due to the importance of lipid biosynthetic fluxes in NAFLD and T2D, tracer methodologies have been developed for their study and quantification. Here, we address novel approaches to measure and quantify DNL using stable isotope tracers. Deuterated water is a widely used tracer for quantifying DNL rates in both animal models and humans. Enrichment of lipid hydrogens from 2 H2O can be resolved and quantified by 2 H NMR and MS spectroscopy of isolated lipids. NMR provides a much higher level of positional enrichment information compared with MS which yields a more detailed picture of lipid biosynthetic. It can also be used to quantify low levels of lipid 13 C enrichment from a second tracer such as [U-13 C]sugar with minimal interference of one tracer with the other. CONCLUSIONS Despite the clear association between elevated DNL activity and increased hepatic triglyceride levels, implementation of non-destructive and novel methods to quantify DNL and its contribution to NAFLD are also of huge interest.
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Affiliation(s)
- Getachew Debas Belew
- Metabolism, Aging and Disease, Center for Neurosciences and Cell Biology, University of Coimbra, Cantanhede, Portugal
| | - John G Jones
- Metabolism, Aging and Disease, Center for Neurosciences and Cell Biology, University of Coimbra, Cantanhede, Portugal
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3
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Li W, Wu L, Sun Q, Yang Q, Xue J, Shi M, Tang H, Zhang J, Liu Q. MicroRNA-191 blocking the translocation of GLUT4 is involved in arsenite-induced hepatic insulin resistance through inhibiting the IRS1/AKT pathway. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 215:112130. [PMID: 33743404 DOI: 10.1016/j.ecoenv.2021.112130] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 03/03/2021] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
Environmental exposure to arsenic can cause a variety of health problems. Epidemiological and experimental studies have established a diabetogenic role for arsenic, but the mechanisms responsible for arsenic-induced impairment of insulin action are unclear. MicroRNAs (miRNAs) are involved in various metabolic disorders, particularly in the development of insulin resistance. The present study investigated whether arsenite, an active form of arsenic, induces hepatic insulin resistance and the mechanisms underlying it. After male C57BL/6J mice were exposed to arsenite (0 or 20 ppm) in drinking water for 12 months, intraperitoneal glucose tolerance tests (IPGTTs) and insulin tolerance tests (ITTs) revealed an arsenite-induced glucose metabolism disorder. Hepatic glycogen levels were lower in arsenite-exposed mice. Further, for livers of mice exposed to arsenite, miR-191 levels were higher, and protein levels of insulin receptor substrate 1 (IRS1), p-IRS1, and phospho-protein kinase B (p-AKT) were lower. Further, glucose transporter 4 (GLUT4) had lower levels on the plasma membrane. For insulin-treated L-02 cells, arsenite decreased glucose consumption and glycogen levels, increased miR-191 levels, and inhibited the IRS1/AKT pathway and the translocation of GLUT4 from the cytoplasm to the plasma membrane. For insulin-treated L-02 cells, the decreases of glucose consumption, glycogen levels, GLUT4 on the plasma membrane, and p-AKT levels induced by arsenite were reversed by SC79 (agonist of AKT) and an miR-191 inhibitor; these effects caused by miR-191 inhibitor were restored by IRS1 siRNA. In insulin-treated L-02 cells, miR-191, via IRS1, was involved in the arsenite-induced decreases of glucose consumption and glycogen levels and in inhibition of the translocation of GLUT4. Thus, miR-191 blocking the translocation of GLUT4 was involved in arsenite-induced hepatic insulin resistance through inhibiting the IRS1/AKT pathway. Our study reveals a mechanism for arsenite-induced hepatic insulin resistance, which provides clues for discovering biomarkers for the development of type 2 diabetes and for prevention and treatment of arsenic poisoning.
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Affiliation(s)
- Wenqi Li
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; China International Cooperation Center for Environment and Human Health, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China
| | - Lu Wu
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; China International Cooperation Center for Environment and Human Health, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China
| | - Qian Sun
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, Guangdong, People's Republic of China
| | - Qianlei Yang
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; China International Cooperation Center for Environment and Human Health, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China
| | - Junchao Xue
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; China International Cooperation Center for Environment and Human Health, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China
| | - Ming Shi
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, Guangdong, People's Republic of China
| | - Huanwen Tang
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, Guangdong, People's Republic of China
| | - Jingshu Zhang
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; Jiangsu Safety Assessment and Research Center for Drug, Pesticide, and Veterinary Drug, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China.
| | - Qizhan Liu
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; China International Cooperation Center for Environment and Human Health, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China.
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4
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Determining the contribution of a high-fructose corn syrup formulation to hepatic glycogen synthesis during ad-libitum feeding in mice. Sci Rep 2020; 10:12852. [PMID: 32733017 PMCID: PMC7393509 DOI: 10.1038/s41598-020-69820-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 07/06/2020] [Indexed: 11/28/2022] Open
Abstract
Excessive sugar intake including high-fructose corn syrup (HFCS) is implicated in the rise of obesity, insulin resistance and non-alcoholic fatty liver disease. Liver glycogen synthesis is influenced by both fructose and insulin signaling. Therefore, the effect of HFCS on hepatic glycogenesis was evaluated in mice feeding ad-libitum. Using deuterated water: the fraction of glycogen derived from triose-P sources, Krebs cycle substrates, and direct pathway + cycling, was measured in 9 normal-chow fed mice (NC) and 12 mice fed normal chow plus a 55% fructose/45% glucose mix in the drinking water at 30% w/v (HFCS-55). This was enriched with [U-13C]fructose or [U-13C]glucose to determine the contribution of each to glycogenesis. For NC, direct pathway + cycling, Krebs cycle, and triose-P sources accounted for 66 ± 0.7%, 23 ± 0.8% and 11 ± 0.4% of glycogen synthesis, respectively. HFCS-55 mice had similar direct pathway + cycling (64 ± 1%) but lower Krebs cycle (12 ± 1%, p < 0.001) and higher triose-P contributions (24 ± 1%, p < 0.001). HFCS-55-fructose contributed 17 ± 1% via triose-P and 2 ± 0% via Krebs cycle. HFCS-55-glucose contributed 16 ± 3% via direct pathway and 1 ± 0% via Krebs cycle. In conclusion, HFCS-55 supplementation resulted in similar hepatic glycogen deposition rates. Indirect pathway contributions shifted from Krebs cycle to Triose-P sources reflecting HFCS-55-fructose utilization, while HFCS-55-glucose was incorporated almost exclusively by the direct pathway.
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5
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Daurio NA, Wang Y, Chen Y, Zhou H, Carballo-Jane E, Mane J, Rodriguez CG, Zafian P, Houghton A, Addona G, McLaren DG, Zhang R, Shyong BJ, Bateman K, Downes DP, Webb M, Kelley DE, Previs SF. Spatial and temporal studies of metabolic activity: contrasting biochemical kinetics in tissues and pathways during fasted and fed states. Am J Physiol Endocrinol Metab 2019; 316:E1105-E1117. [PMID: 30912961 DOI: 10.1152/ajpendo.00459.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The regulation of nutrient homeostasis, i.e., the ability to transition between fasted and fed states, is fundamental in maintaining health. Since food is typically consumed over limited (anabolic) periods, dietary components must be processed and stored to counterbalance the catabolic stress that occurs between meals. Herein, we contrast tissue- and pathway-specific metabolic activity in fasted and fed states. We demonstrate that knowledge of biochemical kinetics that is obtained from opposite ends of the energetic spectrum can allow mechanism-based differentiation of healthy and disease phenotypes. Rat models of type 1 and type 2 diabetes serve as case studies for probing spatial and temporal patterns of metabolic activity via [2H]water labeling. Experimental designs that capture integrative whole body metabolism, including meal-induced substrate partitioning, can support an array of research surrounding metabolic disease; the relative simplicity of the approach that is discussed here should enable routine applications in preclinical models.
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Affiliation(s)
- Natalie A Daurio
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Yichen Wang
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Ying Chen
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Haihong Zhou
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Ester Carballo-Jane
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Joel Mane
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Carlos G Rodriguez
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Peter Zafian
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Andrea Houghton
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - George Addona
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - David G McLaren
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Rena Zhang
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Bao Jen Shyong
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Kevin Bateman
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Daniel P Downes
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Maria Webb
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - David E Kelley
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Stephen F Previs
- Merck Research Laboratories, Merck & Company, Incorporated, Kenilworth, New Jersey
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6
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Antidiabetic and hepatoprotective activity of the roots of Calanthe fimbriata Franch. Biomed Pharmacother 2019; 111:60-67. [DOI: 10.1016/j.biopha.2018.12.066] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/04/2018] [Accepted: 12/14/2018] [Indexed: 11/20/2022] Open
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7
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Huang H, Lee SH, Sousa-Lima I, Kim SS, Hwang WM, Dagon Y, Yang WM, Cho S, Kang MC, Seo JA, Shibata M, Cho H, Belew GD, Bhin J, Desai BN, Ryu MJ, Shong M, Li P, Meng H, Chung BH, Hwang D, Kim MS, Park KS, Macedo MP, White M, Jones J, Kim YB. Rho-kinase/AMPK axis regulates hepatic lipogenesis during overnutrition. J Clin Invest 2018; 128:5335-5350. [PMID: 30226474 DOI: 10.1172/jci63562] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 09/11/2018] [Indexed: 12/24/2022] Open
Abstract
Obesity is a major risk factor for developing nonalcoholic fatty liver disease (NAFLD). NAFLD is the most common form of chronic liver disease and is closely associated with insulin resistance, ultimately leading to cirrhosis and hepatocellular carcinoma. However, knowledge of the intracellular regulators of obesity-linked fatty liver disease remains incomplete. Here we showed that hepatic Rho-kinase 1 (ROCK1) drives obesity-induced steatosis in mice through stimulation of de novo lipogenesis. Mice lacking ROCK1 in the liver were resistant to diet-induced obesity owing to increased energy expenditure and thermogenic gene expression. Constitutive expression of hepatic ROCK1 was sufficient to promote adiposity, insulin resistance, and hepatic lipid accumulation in mice fed a high-fat diet. Correspondingly, liver-specific ROCK1 deletion prevented the development of severe hepatic steatosis and reduced hyperglycemia in obese diabetic (ob/ob) mice. Of pathophysiological significance, hepatic ROCK1 was markedly upregulated in humans with fatty liver disease and correlated with risk factors clustering around NAFLD and insulin resistance. Mechanistically, we found that hepatic ROCK1 suppresses AMPK activity and a ROCK1/AMPK pathway is necessary to mediate cannabinoid-induced lipogenesis in the liver. Furthermore, treatment with metformin, the most widely used antidiabetes drug, reduced hepatic lipid accumulation by inactivating ROCK1, resulting in activation of AMPK downstream signaling. Taken together, our findings establish a ROCK1/AMPK signaling axis that regulates de novo lipogenesis, providing a unique target for treating obesity-related metabolic disorders such as NAFLD.
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Affiliation(s)
- Hu Huang
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Department of Kinesiology and Physiology, East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, North Carolina, USA
| | - Seung-Hwan Lee
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Inês Sousa-Lima
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Centro de Estudos de Doenҫas Crónicas (CEDOC), Chronic Disease Research Center, NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Sang Soo Kim
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Won Min Hwang
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Yossi Dagon
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Won-Mo Yang
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Sungman Cho
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Min-Cheol Kang
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Ji A Seo
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Division of Endocrinology, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | - Munehiko Shibata
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Hyunsoo Cho
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Getachew Debas Belew
- Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, Coimbra, Portugal
| | - Jinhyuk Bhin
- Center for Plant Aging Research and Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Korea
| | - Bhavna N Desai
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Min Jeong Ryu
- Department of Endocrinology and Metabolism, Chungnam National University School of Medicine, Daejeon, Korea
| | - Minho Shong
- Department of Endocrinology and Metabolism, Chungnam National University School of Medicine, Daejeon, Korea
| | - Peixin Li
- Department of Kinesiology and Physiology, East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, North Carolina, USA.,Department of Comprehensive Surgery Medical and Health Center Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Hua Meng
- Department of Comprehensive Surgery Medical and Health Center Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Byung-Hong Chung
- Department of Nutrition Science, Diabetes Research and Training Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Daehee Hwang
- Center for Plant Aging Research and Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Korea
| | - Min Seon Kim
- Department of Internal Medicine, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea
| | - Kyong Soo Park
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Korea
| | - Maria Paula Macedo
- Centro de Estudos de Doenҫas Crónicas (CEDOC), Chronic Disease Research Center, NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Morris White
- Department of Endocrinology, Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - John Jones
- Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, Coimbra, Portugal
| | - Young-Bum Kim
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Korea
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8
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Rito J, Viegas I, Pardal MA, Metón I, Baanante IV, Jones JG. Disposition of a Glucose Load into Hepatic Glycogen by Direct and Indirect Pathways in Juvenile Seabass and Seabream. Sci Rep 2018; 8:464. [PMID: 29323287 PMCID: PMC5765127 DOI: 10.1038/s41598-017-19087-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 12/19/2017] [Indexed: 02/06/2023] Open
Abstract
In carnivorous fish, conversion of a glucose load to hepatic glycogen is widely used to assess their metabolic flexibility towards carbohydrate utilization, but the activities of direct and indirect pathways in this setting are unclear. We assessed the conversion of an intraperitoneal glucose load (2 g.kg-1) enriched with [U-13C6]glucose to hepatic glycogen in juvenile seabass and seabream. 13C-NMR analysis of glycogen was used to determine the contribution of the load to glycogen synthesis via direct and indirect pathways at 48-hr post-injection. For seabass, [U-13C6]glucose was accompanied by deuterated water and 2H-NMR analysis of glycogen 2H-enrichment, allowing endogenous substrate contributions to be assessed as well. For fasted seabass and seabream, 47 ± 5% and 64 ± 10% of glycogen was synthesized from the load, respectively. Direct and indirect pathways contributed equally (25 ± 3% direct, 21 ± 1% indirect for seabass; 35 ± 7% direct, 29 ± 4% indirect for seabream). In fasted seabass, integration of 2H- and 13C-NMR analysis indicated that endogenous glycerol and anaplerotic substrates contributed an additional 7 ± 2% and 7 ± 1%, respectively. In fed seabass, glucose load contributions were residual and endogenous contributions were negligible. Concluding, direct and indirect pathways contributed equally and substantially to fasting hepatic glycogen repletion from a glucose load in juvenile seabream and seabass.
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Affiliation(s)
- João Rito
- CNC - Center for Neuroscience and Cell Biology, Rua Larga, 1° Piso da FMUC, University of Coimbra, 3004-504, Coimbra, Portugal
- CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Ivan Viegas
- CNC - Center for Neuroscience and Cell Biology, Rua Larga, 1° Piso da FMUC, University of Coimbra, 3004-504, Coimbra, Portugal
- CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Miguel A Pardal
- CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Isidoro Metón
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona (UB), Joan XXIII 27, 08028, Barcelona, Spain
| | - Isabel V Baanante
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona (UB), Joan XXIII 27, 08028, Barcelona, Spain
| | - John G Jones
- CNC - Center for Neuroscience and Cell Biology, Rua Larga, 1° Piso da FMUC, University of Coimbra, 3004-504, Coimbra, Portugal.
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9
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Jayaraman R, Subramani S, Sheik Abdullah SH, Udaiyar M. Antihyperglycemic effect of hesperetin, a citrus flavonoid, extenuates hyperglycemia and exploring the potential role in antioxidant and antihyperlipidemic in streptozotocin-induced diabetic rats. Biomed Pharmacother 2017; 97:98-106. [PMID: 29080465 DOI: 10.1016/j.biopha.2017.10.102] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/16/2017] [Accepted: 10/21/2017] [Indexed: 12/25/2022] Open
Abstract
Diabetes is the major health problem in modern civilization which occurs due to inadequate metabolism of carbohydrate and lipid could cause tremendous changes in the metabolic activities of liver. In this study, we investigated the antihyperglycemic, antioxidant and antihyperlipidemic effects of hesperetin, a citrus flavonoid against streptozotocin (STZ)-induced experimental rats. To stimulate diabetes mellitus, rats were injected with STZ intraperitoneally at a single dose of 45mg/kg. STZ induced rats showed marked increase in the level of plasma glucose and significant reduction in the level of plasma insulin. The activities of carbohydrate metabolic enzymes, hepatic glycogen, lipid profiles, enzymic antioxidants in circulatory system and pancreas, hepatic and renal functional markers were explored. Supplementation with hesperetin (40mg/kg b.w) to STZ-induced experimental rats for 45days established a significant decline in plasma glucose and a marked improvement in plasma insulin and glycogen levels in STZ-induced rats. The altered activities of hepatic glucose metabolic enzymes, lipid profiles, enzymic antioxidants and serum biomarkers of liver and kidney toxicity were restored to almost normal. The acquired outcome were compared with glibenclamide (1mg/kg b.w), a standard oral hypoglycemic drug. Hesperetin treatment was found to be efficient in protecting the normal histological manifestation of hepatic, renal and insulin positive β-cells in STZ induced rats. On the basis of current experimental findings, we concluded that administration of hesperetin attenuates the hyperglycemia and dyslipidemia through ameliorating antioxidant competence in STZ-induced experimental rats.
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Affiliation(s)
- Revathy Jayaraman
- Research and Development Centre, Bharathiyar University, Coimbatore, Tamilnadu, India
| | - Srinivasan Subramani
- Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar 608 002, Tamilnadu, India; Postgraduate and Research Department of Biochemistry, Government Arts College for Women, Krishnagiri 635 002, Tamil Nadu, India.
| | - Shahul Hameed Sheik Abdullah
- Research and Development Centre, Bharathiyar University, Coimbatore, Tamilnadu, India; Department of Chemistry and Biosciences, Sastra University, Srinivasa Ramanujan Centre, Kumbakonam, Tamilnadu, India
| | - Muruganathan Udaiyar
- Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar 608 002, Tamilnadu, India
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10
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Analysis of Mammalian Cell Proliferation and Macromolecule Synthesis Using Deuterated Water and Gas Chromatography-Mass Spectrometry. Metabolites 2016; 6:metabo6040034. [PMID: 27754354 PMCID: PMC5192440 DOI: 10.3390/metabo6040034] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/10/2016] [Accepted: 10/10/2016] [Indexed: 11/16/2022] Open
Abstract
Deuterated water (²H₂O), a stable isotopic tracer, provides a convenient and reliable way to label multiple cellular biomass components (macromolecules), thus permitting the calculation of their synthesis rates. Here, we have combined ²H₂O labelling, GC-MS analysis and a novel cell fractionation method to extract multiple biomass components (DNA, protein and lipids) from the one biological sample, thus permitting the simultaneous measurement of DNA (cell proliferation), protein and lipid synthesis rates. We have used this approach to characterize the turnover rates and metabolism of a panel of mammalian cells in vitro (muscle C2C12 and colon cancer cell lines). Our data show that in actively-proliferating cells, biomass synthesis rates are strongly linked to the rate of cell division. Furthermore, in both proliferating and non-proliferating cells, it is the lipid pool that undergoes the most rapid turnover when compared to DNA and protein. Finally, our data in human colon cancer cell lines reveal a marked heterogeneity in the reliance on the de novo lipogenic pathway, with the cells being dependent on both 'self-made' and exogenously-derived fatty acid.
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11
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Srivastava A, Kowalski GM, Callahan DL, Meikle PJ, Creek DJ. Strategies for Extending Metabolomics Studies with Stable Isotope Labelling and Fluxomics. Metabolites 2016; 6:metabo6040032. [PMID: 27706078 PMCID: PMC5192438 DOI: 10.3390/metabo6040032] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 09/21/2016] [Accepted: 09/28/2016] [Indexed: 12/13/2022] Open
Abstract
This is a perspective from the peer session on stable isotope labelling and fluxomics at the Australian & New Zealand Metabolomics Conference (ANZMET) held from 30 March to 1 April 2016 at La Trobe University, Melbourne, Australia. This report summarizes the key points raised in the peer session which focused on the advantages of using stable isotopes in modern metabolomics and the challenges in conducting flux analyses. The session highlighted the utility of stable isotope labelling in generating reference standards for metabolite identification, absolute quantification, and in the measurement of the dynamic activity of metabolic pathways. The advantages and disadvantages of different approaches of fluxomics analyses including flux balance analysis, metabolic flux analysis and kinetic flux profiling were also discussed along with the use of stable isotope labelling in in vivo dynamic metabolomics. A number of crucial technical considerations for designing experiments and analyzing data with stable isotope labelling were discussed which included replication, instrumentation, methods of labelling, tracer dilution and data analysis. This report reflects the current viewpoint on the use of stable isotope labelling in metabolomics experiments, identifying it as a great tool with the potential to improve biological interpretation of metabolomics data in a number of ways.
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Affiliation(s)
- Anubhav Srivastava
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Melbourne, Victoria, Australia.
| | - Greg M Kowalski
- Institute for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood 3125, Victoria, Australia.
| | - Damien L Callahan
- Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Burwood 3125, Victoria, Australia.
| | - Peter J Meikle
- Baker IDI Heart and Diabetes Institute, Melbourne 3004, Victoria, Australia.
| | - Darren J Creek
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Melbourne, Victoria, Australia.
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12
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Martins FO, Delgado TC, Viegas J, Gaspar JM, Scott DK, O'Doherty RM, Macedo MP, Jones JG. Mechanisms by which the thiazolidinedione troglitazone protects against sucrose-induced hepatic fat accumulation and hyperinsulinaemia. Br J Pharmacol 2016; 173:267-78. [PMID: 26447327 DOI: 10.1111/bph.13362] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 08/13/2015] [Accepted: 09/29/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE Thiazolidinediones (TZD) are known to ameliorate fatty liver in type 2 diabetes. To date, the underlying mechanisms of their hepatic actions remain unclear. EXPERIMENTAL APPROACH Hepatic triglyceride content and export rates were assessed in 2 week high-sucrose-fed Wistar rats treated with troglitazone and compared with untreated high-sucrose rodent controls. Fractional de novo lipogenesis (DNL) contributions to hepatic triglyceride were quantified by analysis of triglyceride enrichment from deuterated water. Hepatic insulin clearance and NO status during a meal tolerance test were also evaluated. KEY RESULTS TZD significantly reduced hepatic triglyceride (P < 0.01) by 48%, decreased DNL contribution to hepatic triglyceride (P < 0.01) and increased postprandial non-esterified fatty acids clearance rates (P < 0.01) in comparison with the high-sucrose rodent control group. During a meal tolerance test, plasma insulin AUC was significantly lower (P < 0.01), while blood glucose and plasma C-peptide levels were not different. Insulin clearance was increased (P < 0.001) by 24% and was associated with a 22% augmentation of hepatic insulin-degrading enzyme activity (P < 0.05). Finally, hepatic NO was decreased by 24% (P < 0.05). CONCLUSIONS Overall, TZD show direct actions on liver by reducing hepatic DNL and increasing hepatic insulin clearance. The alterations in hepatic insulin clearance were associated with changes in insulin-degrading enzyme activity, with possible modulation of NO levels.
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Affiliation(s)
- Fátima O Martins
- Metabolic Control Group, Center for Neurosciences and Cell Biology of Coimbra, Cantanhede, Portugal
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13
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Abstract
The liver has a central role in the regulation of systemic glucose and lipid fluxes during feeding and fasting and also relies on these substrates for its own energy needs. These parallel requirements are met by coordinated control of carbohydrate and lipid fluxes into and out of the Krebs cycle, which is highly tuned to nutrient availability and heavily regulated by insulin and glucagon. During progression of type 2 diabetes, hepatic carbohydrate and lipid biosynthesis fluxes become elevated, thus contributing to hyperglycaemia and hypertriacylglycerolaemia. Over this interval there are also significant fluctuations in hepatic energy state. To date, it is not known to what extent abnormal glucose and lipid fluxes are causally linked to altered energy states. Recent evidence that the glucose-lowering effects of metformin appear to be mediated by attenuation of hepatic energy generation places an additional spotlight on the interdependence of hepatic biosynthetic and oxidative fluxes. The transition from fasting to feeding results in a significant re-direction of hepatic glucose and lipid fluxes and may also incur a temporary hepatic energy deficit. At present, it is not known to what extent these variables are additionally modified by type 2 diabetes and/or non-alcoholic fatty liver disease. Thus, there is a compelling need to measure fluxes through oxidative, gluconeogenic and lipogenic pathways and determine their relationship with hepatic energy state in both fasting and fed conditions. New magnetic resonance-based technologies allow these variables to be non-invasively studied in animal models and humans. This review summarises a presentation given at the symposium entitled 'The liver in focus' at the 2015 annual meeting of the EASD. It is accompanied by two other reviews on topics from this symposium (by Kenneth Cusi, DOI: 10.1007/s00125-016-3952-1 , and by Hannele Yki-Järvinen, DOI: 10.1007/s00125-016-3944-1 ) and a commentary by the Session Chair, Michael Roden (DOI: 10.1007/s00125-016-3911-x ).
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Affiliation(s)
- John G Jones
- Metabolic Control Group, Center for Neurosciences and Cell Biology of Coimbra, UC Biotech, Biocant Park, 3060-197, Cantanhede, Portugal.
- APDP-Diabetes Portugal-Education and Research Center (APDP-ERC), Lisbon, Portugal.
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14
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Viegas I, Jarak I, Rito J, Carvalho RA, Metón I, Pardal MA, Baanante IV, Jones JG. Effects of dietary carbohydrate on hepatic de novo lipogenesis in European seabass (Dicentrarchus labrax L.). J Lipid Res 2016; 57:1264-72. [PMID: 27247346 DOI: 10.1194/jlr.m067850] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Indexed: 02/06/2023] Open
Abstract
Farmed seabass have higher adiposity than their wild counterparts and this is often attributed to carbohydrate (CHO) feeding. Whether this reflects a reduction in fat oxidation, increased de novo lipogenesis (DNL), or both, is not known. To study the effects of high CHO diets on hepatic TG biosynthesis, hepatic TG deuterium ((2)H) enrichment was determined following 6 days in (2)H-enriched tank water for fish fed with a no-CHO control diet (CTRL), and diets with digestible starch (DS) and raw starch (RS). Hepatic fractional synthetic rates (FSRs, percent per day(-1)) were calculated for hepatic TG-glyceryl and FA moieties through (2)H NMR analysis. Glyceryl FSRs exceeded FA FSRs in all cases, indicating active cycling. DS fish did not show increased lipogenic potential compared to CTRL. RS fish had lower glyceryl FSRs compared with the other diets and negligible levels of FA FSRs despite similar hepatic TG levels to CTRL. DS-fed fish showed higher activity for enzymes that can provide NADPH for lipogenesis, relative to CTRL in the case of glucose-6-phosphate dehydrogenase (G6PDH) and relative to RS for both G6PDH and 6-phosphogluconate dehydrogenase. This approach indicated that elevated hepatic adiposity from DS feeding was not attributable to increased DNL.
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Affiliation(s)
- Ivan Viegas
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal Center for Functional Ecology, Department Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
| | - Ivana Jarak
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - João Rito
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal Center for Functional Ecology, Department Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
| | - Rui A Carvalho
- Center for Functional Ecology, Department Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
| | - Isidoro Metón
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Miguel A Pardal
- Center for Functional Ecology, Department Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
| | - Isabel V Baanante
- Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, 08028 Barcelona, Spain
| | - John G Jones
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
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15
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McDonald MW, Murray MR, Grise KN, Olver TD, Dey A, Shoemaker JK, Noble EG, Melling CWJ. The glucoregulatory response to high-intensity aerobic exercise following training in rats with insulin-treated type 1 diabetes mellitus. Appl Physiol Nutr Metab 2016; 41:631-9. [PMID: 27175938 DOI: 10.1139/apnm-2015-0558] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An acute bout of exercise elicits a rapid, potentially deleterious, reduction in blood glucose in patients with type 1 diabetes mellitus (T1DM). In the current study, we examined whether a 10-week aerobic training program could alleviate the rapid exercise-associated reduction in blood glucose through changes in the glucoregulatory hormonal response or increased hepatic glycogen storage in an insulin-treated rat model of T1DM. Thirty-two male Sprague-Dawley rats were divided evenly into 4 groups: non-T1DM sedentary (C) (n = 8), non-T1DM exercised (CX) (n = 8), T1DM sedentary (D) (n = 8), and T1DM exercised (DX) (n = 8). Exercise training consisted of treadmill running for 5 days/week (1 h, 27 m/min, 6% grade) for 10 weeks. T1DM was induced by multiple streptozotocin injections (20 mg/kg) followed by implantation of subcutaneous insulin pellets. At week 1, an acute exercise bout led to a significant reduction in blood glucose in DX (p < 0.05), whereas CX exhibited an increase in blood glucose (p < 0.05). During acute exercise, serum epinephrine was increased in both DX and CX (p < 0.05), whereas serum glucagon was increased during recovery only in CX (p < 0.01). Following aerobic training in DX, the exercise-mediated reduction in blood glucose remained; however, serum glucagon increased to the same extent as in CX (p < 0.05). DX exhibited significantly less hepatic glycogen (p < 0.001) despite elevations in glycogenic proteins in the liver (p < 0.05). Elevated serum epinephrine and decreased hepatic adrenergic receptor expression were also evident in DX (p < 0.05). In summary, despite aerobic training in DX, abrupt blood glucose reductions and hepatic glycogen deficiencies were evident. These data suggest that sympathetic overactivity may contribute to deficiencies in hepatic glycogen storage.
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Affiliation(s)
- Matthew W McDonald
- a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada
| | - Michael R Murray
- a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada
| | - Kenneth N Grise
- a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada
| | - T Dylan Olver
- a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada
| | - Adwitia Dey
- a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada
| | - J Kevin Shoemaker
- a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada.,b Lawson Health Research Institute, University of Western Ontario, London, ON, Canada
| | - Earl G Noble
- a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada.,b Lawson Health Research Institute, University of Western Ontario, London, ON, Canada
| | - C W James Melling
- a School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada.,c School of Health Studies, Faculty of Health Sciences, University of Western Ontario, 3M Centre, Room 2213, London, ON, N6A 5B9 Canada
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16
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Wu Y, Wang W, Liu L. Effect of β-anhydroicaritin on the expression levels of tumor necrosis factor-α and matrix metalloproteinase-3 in periodontal tissue of diabetic rats. Mol Med Rep 2015; 12:1829-37. [PMID: 25847066 PMCID: PMC4464411 DOI: 10.3892/mmr.2015.3591] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Accepted: 02/26/2015] [Indexed: 11/20/2022] Open
Abstract
The present study aimed to investigate the effect of β-anhydroicaritin on the expression levels of tumor necrosis factor (TNF)-α and matrix metalloproteinase (MMP)-3, and the pathological changes in the periodontal tissue of diabetic rats. Male Wistar rats (n=40; three months old) were randomly divided into four groups: Normal control group, diabetes group, diabetes + β-anhydroicaritin group and diabetes + urate group, (n=10 in each group). Following an overnight fast, diabetes was induced by intraperitoneal injection of streptozocin. The rats were maintained for 12 weeks and the blood sugar, urine sugar and body weight were assessed in week 12. Histological changes of the periodontal tissues were observed by hematoxylin and eosin staining, and the expression levels of TNF-α and MMP-3 were observed by immunohistochemistry. Following 12 weeks, the TNF-α grey value in the diabetes group was significantly lower compared with that in the control group (P<0.05), while no significant difference was observed between TNF-α levels in the diabetes + β-anhydroicaritin group, diabetes + urate group and the control group (P>0.05). However, TNF-α levels in the diabetes + β-anhdroicaritin group and diabetes + urate group were significantly higher compared with those in the diabetes group (P<0.05), and those in the diabetes + β-anhydroicaritin group were lower compared with those in the diabetes + urate group (P<0.05). The MMP-3 grey value in the diabetes group was significantly lower compared with that in the control group (P<0.05), while no significant difference was observed between MMP-3 levels in the diabetes + β-anhydroicaritin group, diabetes + urate group and the control group (P>0.05). However, MMP-3 levels the diabetes + β-anhydroicaritin group and diabetes + urate group were significantly higher compared with those in the diabetes group (P<0.05), and those in the diabetes + β-anhydroicaritin group were lower compared with those in the diabetes + urate group (P<0.01). β-anhydroicaritin normalized the expression levels of TNF-α and MMP-3 in the periodontal tissue of diabetic rats and led to the recovery of the changes in the morphological structure of the periodontal tissue.
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Affiliation(s)
- Yingtao Wu
- Department of Periodontology and Oral Mucosa Diseases, Qingdao Stomatological Hospital, Qingdao, Shandong 266001, P.R. China
| | - Wanchun Wang
- Department of Periodontology and Oral Mucosa Diseases, Qingdao Stomatological Hospital, Qingdao, Shandong 266001, P.R. China
| | - Lian Liu
- Department of Acupuncture and Moxibustion, Qingdao Hiser Medical Group, Qingdao, Shandong 266001, P.R. China
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17
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Identifying Sources of Hepatic Lipogenic Acetyl-CoA Using Stable Isotope Tracers and NMR. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/109252] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The role of hepatic de novo lipogenesis (DNL) in promoting fatty liver disease and hypertriglyceridemia during excessive nutrient intake is becoming firmly established. Certain nutrients such as fructose promote hepatic DNL activity and this has been at least partly attributed to their efficient conversion to the acetyl-CoA precursors of DNL. However, tracer studies indicate a paradoxically low level of fructose incorporation into lipids, which begs the question of what the actual lipogenic acetyl-CoA sources are under these and other conditions. Here, we describe novel approaches for measuring substrate contributions to lipogenic hepatic acetyl-CoA using 13C-tracers and 13C-NMR analysis of lipids and acetyl-CoA probes. We review and address aspects of hepatic intermediary fluxes and acetyl-CoA compartmentation that can confound the relationship between 13C-precursor substrate and lipogenic 13C-acetyl-CoA enrichments and demonstrate novel methodologies that can provide realistic estimates of 13C-enriched substrate contributions to DNL. The most striking realization is that the principal substrate contributors to lipogenic acetyl-CoA have yet to be identified, but they are probably not the so-called “lipogenic substrates” such as fructose. The proposed methods may improve our insight into the nutrient sources of DNL under various feeding and disease states.
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18
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Disposition of [U-2H7]glucose into hepatic glycogen in rat and in seabass. Comp Biochem Physiol A Mol Integr Physiol 2013; 166:316-22. [PMID: 23838145 DOI: 10.1016/j.cbpa.2013.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 06/17/2013] [Accepted: 07/01/2013] [Indexed: 11/20/2022]
Abstract
The stimulation of hepatic glycogenesis is a ubiquitous response to a glucose challenge and quantifying its contribution to glucose uptake informs its role in restoring euglycemia. Glycogenesis can be quantified with labeled water provided that exchange of glucose-6-phosphate hydrogen 2 (G6P-H2) and body water via glucose-6-phosphate isomerase, and exchange of positions 4, 5 and 6 hydrogens (G6P-H456) via transaldolase, are known. These exchanges were quantified in 24-h fasted rats (Rattus norvegicus; n=6) and 21-day fasted seabass (Dicentrarchus labrax; n=8) by administration of a glucose load (2000mg·kg(-1)) enriched with [U-(2)H7]glucose and by quantifying hepatic glycogen (2)H-enrichments after 2h (rats) and 48h (seabass). Direct pathway contributions of the glucose load to glycogenesis were also estimated. G6P-H2 and body water exchange was 61±1% for rat and 47±3% for seabass. Transaldolase-mediated exchange of G6P-H456 was 5±1% for rat and 10±1% for seabass. Conversion of the glucose load to hepatic glycogen was significant in seabass (249±54mg·kg(-1)) but negligible in rats (12±1mg·kg(-1)). Preload plasma glucose levels were similar for seabass and rats (3.3±0.7 and 4.4±0.1mmol·L(-1), respectively) but post-load plasma glucose was significantly higher in seabass compared to rats (14.6±1.8 versus 5.8±0.3mmol·L(-1), p<0.01). In conclusion, G6P-H2 and body water exchange is incomplete for both species and has to be accounted for in estimating hepatic glycogen synthesis and direct pathway activities with labeled water tracers. Transaldolase-mediated exchange is insignificant. Hepatic direct pathway glycogenesis plays a prominent role in seabass glucose load disposal, but a negligible role in the rat.
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