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du Preez R, Wanyonyi S, Mouatt P, Panchal SK, Brown L. Saskatoon Berry Amelanchier alnifolia Regulates Glucose Metabolism and Improves Cardiovascular and Liver Signs of Diet-Induced Metabolic Syndrome in Rats. Nutrients 2020; 12:nu12040931. [PMID: 32230955 PMCID: PMC7231198 DOI: 10.3390/nu12040931] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 12/13/2022] Open
Abstract
Saskatoon berry (Amelanchier alnifolia) is a potential functional food containing anthocyanins and flavonols, as well as ellagitannins and phenolic acids. We have determined the potential therapeutic effects of Saskatoon berry in diet-induced metabolic syndrome. Nine- to ten-week-old male Wistar rats were randomly assigned to four groups. Two groups were fed on control diets, either corn starch (C) or high-carbohydrate, high-fat diet (H) respectively, for 16 weeks. Two further groups were fed on C or H diet for 16 weeks with Saskatoon berry powder added to the diet for the final 8 weeks (CSSK, HSSK). After 16 weeks, H rats showed symptoms of metabolic syndrome, including increased body weight, visceral adiposity, systolic blood pressure, cardiac fibrosis, plasma concentrations of triglycerides and non-esterified fatty acids, and plasma activities of alanine transaminase and aspartate transaminase. Saskatoon berry intervention normalised body weight and adiposity, improved glucose tolerance, decreased systolic blood pressure, improved heart and liver structure and function with decreased infiltration of inflammatory cells, and decreased plasma total cholesterol. Further, Saskatoon berry normalised liver expression of hexokinase 1 and glycogen phosphorylase and increased glucose 6-phosphatase relative to H rats. These results suggest that Saskatoon berry regulates glycolysis, gluconeogenesis and glycogenesis to improve metabolic syndrome.
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Affiliation(s)
- Ryan du Preez
- Functional Foods Research Group, University of Southern Queensland, Toowoomba, QLD 4350, Australia; (R.d.P.); (S.W.); (S.K.P.)
- School of Health and Wellbeing, University of Southern Queensland, Toowoomba, QLD 4350, Australia
| | - Stephen Wanyonyi
- Functional Foods Research Group, University of Southern Queensland, Toowoomba, QLD 4350, Australia; (R.d.P.); (S.W.); (S.K.P.)
| | - Peter Mouatt
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW 2480, Australia;
| | - Sunil K. Panchal
- Functional Foods Research Group, University of Southern Queensland, Toowoomba, QLD 4350, Australia; (R.d.P.); (S.W.); (S.K.P.)
| | - Lindsay Brown
- Functional Foods Research Group, University of Southern Queensland, Toowoomba, QLD 4350, Australia; (R.d.P.); (S.W.); (S.K.P.)
- School of Health and Wellbeing, University of Southern Queensland, Toowoomba, QLD 4350, Australia
- Correspondence: ; Tel.: +61-7-3812-6366
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Westermeier F, Holyoak T, Asenjo JL, Gatica R, Nualart F, Burbulis I, Bertinat R. Gluconeogenic Enzymes in β-Cells: Pharmacological Targets for Improving Insulin Secretion. Trends Endocrinol Metab 2019; 30:520-531. [PMID: 31213347 DOI: 10.1016/j.tem.2019.05.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/14/2019] [Accepted: 05/16/2019] [Indexed: 02/06/2023]
Abstract
Pancreatic β-cells express the gluconeogenic enzymes glucose 6-phosphatase (G6Pase), fructose 1,6-bisphosphatase (FBP), and phosphoenolpyruvate (PEP) carboxykinase (PCK), which modulate glucose-stimulated insulin secretion (GSIS) through their ability to reverse otherwise irreversible glycolytic steps. Here, we review current knowledge about the expression and regulation of these enzymes in the context of manipulating them to improve insulin secretion in diabetics. Because the regulation of gluconeogenic enzymes in β-cells is so poorly understood, we propose novel research avenues to study these enzymes as modulators of insulin secretion and β-cell dysfunction, with especial attention to FBP, which constitutes an attractive target with an inhibitor under clinical evaluation at present.
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Affiliation(s)
- Francisco Westermeier
- FH JOANNEUM Gesellschaft mbH University of Applied Sciences, Institute of Biomedical Science, Eggenberger Allee 13, 8020 Graz, Austria
| | - Todd Holyoak
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Joel L Asenjo
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Independencia 631, 5110566 Valdivia, Chile
| | - Rodrigo Gatica
- Escuela de Veterinaria, Facultad de Ciencias, Universidad Mayor, La Pirámide 5750, 8580745 Santiago, Chile
| | - Francisco Nualart
- Centro de Microscopía Avanzada, CMA BIO, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160 C, 4030000 Concepción, Chile
| | - Ian Burbulis
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Jordan Hall Room 6022, 1340 Jefferson Park Avenue, Charlottesville, VA 22908, USA; Escuela de Medicina, Universidad San Sebastián, Sede Patagonia, Lago Panguipulli 1390, 5501842 Puerto Montt, Chile
| | - Romina Bertinat
- Centro de Microscopía Avanzada, CMA BIO, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160 C, 4030000 Concepción, Chile.
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Regulatory principles in metabolism–then and now. Biochem J 2016; 473:1845-57. [DOI: 10.1042/bcj20160103] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 03/21/2016] [Indexed: 12/22/2022]
Abstract
The importance of metabolic pathways for life and the nature of participating reactions have challenged physiologists and biochemists for over a hundred years. Eric Arthur Newsholme contributed many original hypotheses and concepts to the field of metabolic regulation, demonstrating that metabolic pathways have a fundamental thermodynamic structure and that near identical regulatory mechanisms exist in multiple species across the animal kingdom. His work at Oxford University from the 1970s to 1990s was groundbreaking and led to better understanding of development and demise across the lifespan as well as the basis of metabolic disruption responsible for the development of obesity, diabetes and many other conditions. In the present review we describe some of the original work of Eric Newsholme, its relevance to metabolic homoeostasis and disease and application to present state-of-the-art studies, which generate substantial amounts of data that are extremely difficult to interpret without a fundamental understanding of regulatory principles. Eric's work is a classical example of how one can unravel very complex problems by considering regulation from a cell, tissue and whole body perspective, thus bringing together metabolic biochemistry, physiology and pathophysiology, opening new avenues that now drive discovery decades thereafter.
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Butler AA, Kozak LP. A recurring problem with the analysis of energy expenditure in genetic models expressing lean and obese phenotypes. Diabetes 2010; 59:323-9. [PMID: 20103710 PMCID: PMC2809965 DOI: 10.2337/db09-1471] [Citation(s) in RCA: 228] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Andrew A. Butler
- Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, Florida
| | - Leslie P. Kozak
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
- Corresponding author: Leslie Kozak,
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Marin S, Lee WN, Bassilian S, Lim S, Boros L, Centelles J, FERNáNDEZ-NOVELL J, Guinovart J, Cascante M. Dynamic profiling of the glucose metabolic network in fasted rat hepatocytes using [1,2-13C2]glucose. Biochem J 2004; 381:287-94. [PMID: 15032751 PMCID: PMC1133787 DOI: 10.1042/bj20031737] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2003] [Revised: 03/15/2004] [Accepted: 03/22/2004] [Indexed: 01/19/2023]
Abstract
Recent studies in metabolic profiling have underscored the importance of the concept of a metabolic network of pathways with special functional characteristics that differ from those of simple reaction sequences. The characterization of metabolic functions requires the simultaneous measurement of substrate fluxes of interconnecting pathways. Here we present a novel stable isotope method by which the forward and reverse fluxes of the futile cycles of the hepatic glucose metabolic network are simultaneously determined. Unlike previous radio-isotope methods, a single tracer [1,2-13C2]D-glucose and mass isotopomer analysis is used. Changes in fluxes of substrate cycles, in response to several gluconeogenic substrates, in isolated fasted hepatocytes from male Wistar rats were measured simultaneously. Incubation with these substrates resulted in a change in glucose-6-phosphatase/glucokinase and glycolytic/gluconeogenic flux ratios. Different net redistributions of intermediates in the glucose network were observed, resulting in distinct metabolic phenotypes of the fasted hepatocytes in response to each substrate condition. Our experimental observations show that the constraints of concentrations of shared intermediates, and enzyme kinetics of intersecting pathways of the metabolic network determine substrate redistribution throughout the network when it is perturbed. These results support the systems-biology notion that network analysis provides an integrated view of the physiological state. Interaction between metabolic intermediates and glycolytic/gluconeogenic pathways is a basic element of cross-talk in hepatocytes, and may explain some of the difficulties in genotype and phenotype correlation.
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Affiliation(s)
- Silvia Marin
- *Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Martí i Franquès 1, Barcelona 08028, Spain
- †Centre de Recerca en Química Teòrica (CeRQT), Parc Científic de Barcelona, Universitat de Barcelona, Barcelona 08028, Spain
| | - W.-N. Paul Lee
- ‡Harbor-UCLA Research and Education Institute, UCLA School of Medicine, 1124 West Carson St. RB 1, Torrance, CA 90502, U.S.A
| | - Sara Bassilian
- ‡Harbor-UCLA Research and Education Institute, UCLA School of Medicine, 1124 West Carson St. RB 1, Torrance, CA 90502, U.S.A
| | - Shu Lim
- ‡Harbor-UCLA Research and Education Institute, UCLA School of Medicine, 1124 West Carson St. RB 1, Torrance, CA 90502, U.S.A
| | - Laszlo G. Boros
- ‡Harbor-UCLA Research and Education Institute, UCLA School of Medicine, 1124 West Carson St. RB 1, Torrance, CA 90502, U.S.A
| | - Josep J. Centelles
- *Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Martí i Franquès 1, Barcelona 08028, Spain
- †Centre de Recerca en Química Teòrica (CeRQT), Parc Científic de Barcelona, Universitat de Barcelona, Barcelona 08028, Spain
| | - Josep Maria FERNáNDEZ-NOVELL
- *Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Martí i Franquès 1, Barcelona 08028, Spain
| | - Joan J. Guinovart
- *Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Martí i Franquès 1, Barcelona 08028, Spain
- §Institut de Recerca Biomèdica de Barcelona (IRBB), Parc Científic de Barcelona, Universitat de Barcelona, Barcelona 08028, Spain
| | - Marta Cascante
- *Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Martí i Franquès 1, Barcelona 08028, Spain
- †Centre de Recerca en Química Teòrica (CeRQT), Parc Científic de Barcelona, Universitat de Barcelona, Barcelona 08028, Spain
- To whom correspondence should be addressed (e-mail )
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Liu X, Rossmeisl M, McClaine J, Riachi M, Harper ME, Kozak LP. Paradoxical resistance to diet-induced obesity in UCP1-deficient mice. J Clin Invest 2003; 111:399-407. [PMID: 12569166 PMCID: PMC151850 DOI: 10.1172/jci15737] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The availability of mice lacking the mitochondrial uncoupling protein UCP1, has provided an opportunity to analyze the relationship between the capacity for energy expenditure and the development of obesity in response to a high-fat, high-sucrose diet. Congenic UCP1-deficient mice on a C57BL/6J genetic background show a temperature-dependent resistance to diet-induced obesity when compared with wild-type mice. This resistance, which occurs at 20 degrees C, is quickly reversed when the ambient temperature is increased to 27 degrees C. At 20 degrees C, total oxygen consumption and physical activity of mutant and wild-type mice are indistinguishable; however, body temperature is higher in UCP1-deficient mice by 0.1-0.3 degrees C, and respiratory quotient is slightly reduced. A reduced respiratory quotient, together with elevated beta-hydroxybutyrate and reduced plasma fatty acid levels, suggests that the mutants oxidize a greater proportion of fat than wild-type mice, and that this possibly accounts for the resistance to diet-induced obesity. Although shivering is one alternative mechanism of thermogenesis that is probably used in UCP1-deficient mice, whether there are others remains to be determined. Nevertheless, our study underscores the paradox that elimination of the major thermogenic mechanism in the animal reduces rather than increases metabolic efficiency. We propose that in the absence of nonshivering thermogenesis, alternative, calorically more costly pathways of metabolism must be used to maintain body temperature.
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Affiliation(s)
- Xiaotuan Liu
- Pennington Biomedical Research Center, Baton Rouge, Louisiana 70808, USA
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Liu X, Rossmeisl M, McClaine J, Kozak LP. Paradoxical resistance to diet-induced obesity in UCP1-deficient mice. J Clin Invest 2003. [DOI: 10.1172/jci200315737] [Citation(s) in RCA: 228] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Cohen DM, Bergman RN. Improved estimation of anaplerosis in heart using 13C NMR. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:E1228-42. [PMID: 9435540 DOI: 10.1152/ajpendo.1997.273.6.e1228] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Anaplerotic enzymes, such as pyruvate carboxylase or malic enzyme, catalyze reactions that fill up the pools of the citric acid cycle (CAC), thereby increasing the total mass of CAC intermediates. Relative anaplerosis (y) denotes the ratio of anaplerotic flux to the flux catalyzed by citrate synthase. We examine conventional methods [C. R. Malloy, A. D. Sherry, and F. M. H. Jeffrey. J. Biol. Chem. 263:6964-6971, 1988; C. R. Malloy, A. D. Sherry, and F. M. H. Jeffrey. Am. J. Physiol. 259 (Heart Circ. Physiol. 28): H987-H995, 1990] of measurement of y using 13C-labeled precursors and analysis of [13C]glutamate labeling by nuclear magnetic resonance (NMR) spectroscopy. Through mathematical analysis and computer simulation, we show that isotopic enrichment of the pool of pyruvate that is substrate for anaplerosis will severely decrease the accuracy of estimates of y made with conventional methods no matter how small the mass of the pool of pyruvate. Suppose that the recycling parameter R denotes the fraction of molecules of pyruvate that contain carbons derived from intermediates of the CAC. Each means of estimation of relative anaplerosis in the peer-reviewed literature assumes that R = O, although this assumption has not been confirmed by experiment. We show that conventional formulas, using either fractional enrichments of carbons or isotopomer analysis, actually estimate at most y.(1 - R) instead of y during administration of [2-13C]acetate and unlabeled pyruvate. Using a new formula for estimation of y, we recalculate values of y from the literature and find them approximately 50% too low. We assume that all anaplerosis is via pyruvate and that the difference in isotopic enrichment between cytosolic and mitochondrial malate is negligible.
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Affiliation(s)
- D M Cohen
- Department of Physiology and Biophysics, University of Southern California School of Medicine, Los Angeles 90033, USA
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Crabtree B, Newsholme EA, Reppas NB. Principles of Regulation and Control in Biochemistry: A Pragmatic, Flux‐Oriented Approach. Compr Physiol 1997. [DOI: 10.1002/cphy.cp140105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Moskovitz B, Katz Y, Singer P, Nativ O, Rosenberg B. Glutamine metabolism and utilization: relevance to major problems in health care. Pharmacol Res 1994; 30:61-71. [PMID: 7831196 DOI: 10.1016/1043-6618(94)80088-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Glutamine plays an important role in normal and pathophysiological states. In this review we describe the biochemical synthesis and degradation pathways of glutamine, as well as its utilization by the immune system and in rapidly dividing cells. Also discussed are glutamine behaviour in catabolic states and the therapeutic implications of this amino acid in total parenteral nutrition, digestive diseases and cancer.
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Affiliation(s)
- B Moskovitz
- Department of Urology, Bnai Zion Medical Center, Haifa, Israel
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Young VR, Yu YM, Fukagawa NK. Protein and energy interactions throughout life. Metabolic basis and nutritional implications. ACTA PAEDIATRICA SCANDINAVICA. SUPPLEMENT 1991; 373:5-24. [PMID: 1927528 DOI: 10.1111/j.1651-2227.1991.tb18147.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We review selected aspects of the interactions between protein and energy in human metabolism and nutrition. Following a short account of the underlying metabolic basis for the effects of energy on protein metabolism, the contribution made by whole body protein turnover to the metabolic rate is discussed, including the relationship between protein turnover and energy metabolism at different phases of life. The effects of changes in energy metabolism and intake on the nitrogen economy of the host are also reviewed briefly and we explore the relationship between amino acid oxidation and requirements for indispensable amino acids. Interactions between energy and protein metabolism need to be investigated in greater detail and also they must be considered in relation to further attempts to establish more precisely energy and amino acid requirements of people under various circumstances.
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Affiliation(s)
- V R Young
- Laboratory of Human Nutrition, Massachusetts Institute of Technology, Cambridge
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Kelly JM, McBride BW. The sodium pump and other mechanisms of thermogenesis in selected tissues. Proc Nutr Soc 1990; 49:185-202. [PMID: 2172993 DOI: 10.1079/pns19900023] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- J M Kelly
- Department of Animal and Poultry Science, University of Guelph, Ontario, Canada
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Abstract
The effect of 48-hour starvation on glucose metabolism was studied in six non-diabetic, normal weight men using a hyperinsulinemic (100 mU/min/m2) glucose clamp (3.5 mmol/L). The rate of glucose oxidation was calculated from measurements of respiratory gas exchange, after allowing for the oxidation of ketones and of protein. During the glucose clamp, the whole body glucose disposal rate decreased from 39.8 (SEM 4.6) mumol/kg/min in the fed state to 24.1 (2.1) mumol/kg/min in the starved state (P less than .01), consistent with insulin "resistance." The glucose oxidation rate decreased from 21.8 (1.3) to 3.9 (1.4) mumol/kg/min with starvation (P less than .001), but the nonoxidative glucose disposal rate was unchanged (18.0 [3.9] mumol/kg/min normally fed, and 20.2 [1.2] mumol/kg/min starved). With starvation, the rate of glucose uptake in the forearm during the glucose clamp was reduced from 59.4 to 15.4 mumol/min/L forearm (SE 5.6, P less than .01, ANOVA). There was a significant net increase in thermogenesis during the glucose clamp in the normally fed state (0.27 [0.08] kJ/min, P less than .01, ANOVA), but not following starvation (0.11 [0.09] kJ/min, NS, ANOVA). Therefore, starvation caused decreases in oxidative glucose disposal and in forearm glucose uptake; despite the whole body nonoxidative disposal rate of glucose being unchanged, the associated net thermogenic response was diminished.
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Affiliation(s)
- P I Mansell
- Department of Physiology and Pharmacology, Queen's Medical Centre, Nottingham, England
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