1
|
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.
Collapse
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
| |
Collapse
|
2
|
Romero-Velarde E, Delgado-Franco D, García-Gutiérrez M, Gurrola-Díaz C, Larrosa-Haro A, Montijo-Barrios E, Muskiet FAJ, Vargas-Guerrero B, Geurts J. The Importance of Lactose in the Human Diet: Outcomes of a Mexican Consensus Meeting. Nutrients 2019; 11:E2737. [PMID: 31718111 PMCID: PMC6893676 DOI: 10.3390/nu11112737] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/04/2019] [Accepted: 11/08/2019] [Indexed: 12/12/2022] Open
Abstract
Lactose is a unique component of breast milk, many infant formulas and dairy products, and is widely used in pharmaceutical products. In spite of that, its role in human nutrition or lactose intolerance is generally not well-understood. For that reason, a 2-day-long lactose consensus meeting with health care professionals was organized in Mexico to come to a set of statements for which consensus could be gathered. Topics ranging from lactase expression to potential health benefits of lactose were introduced by experts, and that was followed by a discussion on concept statements. Interestingly, lactose does not seem to induce a neurological reward response when consumed. Although lactose digestion is optimal, it supplies galactose for liver glycogen synthesis. In infants, it cannot be ignored that lactose-derived galactose is needed for the synthesis of glycosylated macromolecules. At least beyond infancy, the low glycemic index of lactose might be metabolically beneficial. When lactase expression decreases, lactose maldigestion may lead to lactose intolerance symptoms. In infancy, the temporary replacing of lactose by other carbohydrates is only justified in case of severe intolerance symptoms. In those who show an (epi)genetic decrease or absence of lactase expression, a certain amount (for adults mostly up to 12 g per portion) of lactose can still be consumed. In these cases, lactose shows beneficial intestinal-microbiota-shaping effects. Avoiding lactose-containing products may imply a lower intake of other important nutrients, such as calcium and vitamin B12 from dairy products, as well as an increased intake of less beneficial carbohydrates.
Collapse
Affiliation(s)
- Enrique Romero-Velarde
- Instituto de Nutrición Humana, Universidad de Guadalajara and Hospital Civil de Guadalajara “Dr. Juan I. Menchaca”, 44340 Guadalajara, Jalisco, Mexico
| | - Dagoberto Delgado-Franco
- Neonatology Department. ABC Medical Center, 01120 Mexico City and Instituto Tecnológico de Estudios Superiores de Monterrey, 64849 Monterrey, Mexico;
| | | | - Carmen Gurrola-Díaz
- Departamento de Biología Molecular y Genómica. Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, 44340 Guadalajara, Jalisco, Mexico; (C.G.-D.); (B.V.-G.)
| | - Alfredo Larrosa-Haro
- Instituto de Nutrición Humana, Universidad de Guadalajara, 44340 Guadalajara, Jalisco, Mexico;
| | - Ericka Montijo-Barrios
- Servicio de Gastroenterología. Instituto Nacional de Pediatría, 04530 Mexico City, Mexico;
| | - Frits A. J. Muskiet
- Laboratory Medicine, University Medical Center Groningen and University of Groningen, 9713 GZ Groningen, The Netherlands;
| | - Belinda Vargas-Guerrero
- Departamento de Biología Molecular y Genómica. Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, 44340 Guadalajara, Jalisco, Mexico; (C.G.-D.); (B.V.-G.)
| | - Jan Geurts
- FrieslandCampina, 3818 LEAmersfoort, The Netherlands;
| |
Collapse
|
3
|
Bouwman LMS, Swarts HJM, Fernández-Calleja JMS, van der Stelt I, Schols H, Oosting A, Keijer J, van Schothorst EM. Partial replacement of glucose by galactose in the post-weaning diet improves parameters of hepatic health. J Nutr Biochem 2019; 73:108223. [PMID: 31665674 DOI: 10.1016/j.jnutbio.2019.108223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 06/24/2019] [Accepted: 07/31/2019] [Indexed: 01/23/2023]
Abstract
Replacing part of glucose with galactose in the post-weaning diet beneficially affects later life metabolic health in female mice. The liver is the main site of galactose metabolism, but the direct effects of this dietary intervention on the liver in the post-weaning period are not known. The aim of this study was to elucidate this. Weanling female mice (C57BL/6JRccHsd) were fed a starch containing diet with glucose (32 en%) monosaccharide (GLU), or a diet with glucose and galactose (1:1 both 16 en%) (GLU+GAL). Body weight, body composition, and food intake were determined weekly. After 3 weeks, mice were sacrificed, and serum and liver tissues were collected. Global hepatic mRNA expression was analyzed and hepatic triglyceride (TG) and glycogen contents were determined by enzymatic assays. Body weight and body composition were similar in both groups, despite higher food intake in mice on GLU+GAL diet. Hepatic TG content was lower in GLU+GAL-fed than GLU-fed females, while glycogen levels were unaffected. Analysis of global expression patterns of hepatic mRNA showed that mainly inflammation-related pathways were affected by the diet, which were predominantly downregulated in GLU+GAL-fed females compared to GLU-fed females. This reduction in inflammation in GLU+GAL-fed females was also reflected by decreased serum concentrations of acute phase protein Serum amyloid A 3. In conclusion, replacing part of glucose with galactose in the post-weaning diet reduces hepatic TG content and hepatic inflammation.
Collapse
Affiliation(s)
- Lianne M S Bouwman
- Wageningen University, Human and Animal Physiology, Wageningen, The Netherlands
| | - Hans J M Swarts
- Wageningen University, Human and Animal Physiology, Wageningen, The Netherlands
| | | | - Inge van der Stelt
- Wageningen University, Human and Animal Physiology, Wageningen, The Netherlands
| | - Henk Schols
- Wageningen University, Laboratory of Food Chemistry, Wageningen, The Netherlands
| | | | - Jaap Keijer
- Wageningen University, Human and Animal Physiology, Wageningen, The Netherlands
| | | |
Collapse
|
4
|
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.
Collapse
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.
| |
Collapse
|
5
|
Hui H, Ma W, Cui J, Gong M, Wang Y, Zhang Y, He T, Bi Y, He Y. Periodic acid‑Schiff staining method for function detection of liver cells is affected by 2% horse serum in induction medium. Mol Med Rep 2017; 16:8062-8068. [PMID: 28944920 PMCID: PMC5779889 DOI: 10.3892/mmr.2017.7587] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 03/08/2017] [Indexed: 02/06/2023] Open
Abstract
Developing a thorough understanding of experimental methods of hepatic differentiation in hepatic progenitor cells (HPCs) should expand the knowledge of hepatocyte induction in vitro and may help to develop cell transplantation therapies for the clinical usage of HPCs in liver diseases. A previous induction method effectively induced differentiation and metabolic abilities in HPCs. Periodic acid-Schiff (PAS) staining is used to identify glycogen synthesis and hepatocyte function; however, this method failed to detect induced hepatocytes. The present study aimed to investigate the possible factors affecting the previous confusing results of PAS staining. Removal of single induction factors, including dexamethasone, hepatic growth factor and fibroblast growth factor 4 from the induction media did not restore PAS staining, whereas replacement of 2% horse serum (HS) with 10% fetal bovine serum (FBS) significantly increased the number of PAS positive cells. Following 12 days of basal induction, replacing the induction medium with media containing 10% FBS for 12–72 h significantly improved PAS staining, but did not influence indocyanine green uptake. Furthermore, incubation in induction medium with 10% FBS following 12 days of normal induction did not affect the expression of hepatic markers and mature function of HPCs. Therefore, the present study suggested that 2% HS in the induction medium did not affect the hepatic function of induced cells, but did affect glycogen storage, whereas replacement of medium with 10% FBS in advance of PAS staining may restore the failure of PAS staining in low serum concentrations of induced hepatocytes.
Collapse
Affiliation(s)
- Hui Hui
- Department of Pediatric Surgery, The Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China
| | - Wenjun Ma
- Department of Pediatric Surgery, The Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China
| | - Jiejie Cui
- Stem Cell Biology and Therapy Laboratory, The Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China
| | - Mengjia Gong
- Stem Cell Biology and Therapy Laboratory, The Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China
| | - Yi Wang
- Department of Pediatric Surgery, The Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China
| | - Yuanyuan Zhang
- Stem Cell Biology and Therapy Laboratory, The Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China
| | - Tongchuan He
- Stem Cell Biology and Therapy Laboratory, The Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China
| | - Yang Bi
- Department of Pediatric Surgery, The Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China
| | - Yun He
- Department of Pediatric Surgery, The Children's Hospital of Chongqing Medical University, Chongqing 400014, P.R. China
| |
Collapse
|
6
|
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.
Collapse
|
7
|
Effect of fasting on the metabolic response of liver to experimental burn injury. PLoS One 2013; 8:e54825. [PMID: 23393558 PMCID: PMC3564862 DOI: 10.1371/journal.pone.0054825] [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: 08/08/2012] [Accepted: 12/17/2012] [Indexed: 12/31/2022] Open
Abstract
Liver metabolism is altered after systemic injuries such as burns and trauma. These changes have been elucidated in rat models of experimental burn injury where the liver was isolated and perfused ex vivo. Because these studies were performed in fasted animals to deplete glycogen stores, thus simplifying quantification of gluconeogenesis, these observations reflect the combined impact of fasting and injury on liver metabolism. Herein we asked whether the metabolic response to experimental burn injury is different in fed vs. fasted animals. Rats were subjected to a cutaneous burn covering 20% of the total body surface area, or to similar procedures without administering the burn, hence a sham-burn. Half of the animals in the burn and sham-burn groups were fasted starting on postburn day 3, and the others allowed to continue ad libitum. On postburn day 4, livers were isolated and perfused for 1 hour in physiological medium supplemented with 10% hematocrit red blood cells. The uptake/release rates of major carbon and nitrogen sources, oxygen, and carbon dioxide were measured during the perfusion and the data fed into a mass balance model to estimate intracellular fluxes. The data show that in fed animals, injury increased glucose output mainly from glycogen breakdown and minimally impacted amino acid metabolism. In fasted animals, injury did not increase glucose output but increased urea production and the uptake of several amino acids, namely glutamine, arginine, glycine, and methionine. Furthermore, sham-burn animals responded to fasting by triggering gluconeogenesis from lactate; however, in burned animals the preferred gluconeogenic substrate was amino acids. Taken together, these results suggest that the fed state prevents the burn-induced increase in hepatic amino acid utilization for gluconeogenesis. The role of glycogen stores and means to increase and/or maintain internal sources of glucose to prevent increased hepatic amino acid utilization warrant further studies.
Collapse
|
8
|
Soares AF, Carvalho RA, Veiga FJ, Alves MG, Martins FO, Viegas I, González JD, Metón I, Baanante IV, Jones JG. Restoration of direct pathway glycogen synthesis flux in the STZ-diabetes rat model by insulin administration. Am J Physiol Endocrinol Metab 2012; 303:E875-85. [PMID: 22850684 DOI: 10.1152/ajpendo.00161.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Type 1 diabetes subjects are characterized by impaired direct pathway synthesis of hepatic glycogen that is unresponsive to insulin therapy. Since it is not known whether this is an irreversible defect of insulin-dependent diabetes, direct and indirect pathway glycogen fluxes were quantified in streptozotocin (STZ)-induced diabetic rats and compared with STZ rats that received subcutaneous or intraperitoneal insulin (I-SC or I-IP). Three groups of STZ rats were studied at 18 days post-STZ treatment. One group was administered I-SC and another I-IP as two daily injections of short-acting insulin at the start of each light and dark period for days 9-18. A third group did not receive any insulin, and a fourth group of nondiabetic rats was used as control. Glycogen synthesis via direct and indirect pathways, de novo lipogenesis, and gluconeogenesis were determined over the nocturnal feeding period using deuterated water. Direct pathway was residual in STZ rats, and glucokinase activity was also reduced significantly from control levels. Insulin administration restored both net glycogen synthesis via the direct pathway and glucokinase activity to nondiabetic control levels and improved the lipogenic pathway despite an inefficient normalization of the gluconeogenic pathway. We conclude that the reduced direct pathway flux is not an irreversible defect of insulin-dependent diabetes.
Collapse
Affiliation(s)
- Ana F Soares
- Center for Neuroscience and Cell Biology, Dept. of Life Sciences, Univ. of Coimbra, Largo Marquês de Pombal, 3004 - 517, Coimbra, Portugal
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Delgado TC, Barosa C, Nunes PM, Scott DK, O'Doherty RM, Cerdán S, Geraldes CFGC, Jones JG. Effect of cyclosporine A on hepatic carbohydrate metabolism and hepatic gene expression in rat. Expert Opin Drug Metab Toxicol 2012; 8:1223-30. [DOI: 10.1517/17425255.2012.709500] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
10
|
Hepatic glycogen synthesis in farmed European seabass (Dicentrarchus labrax L.) is dominated by indirect pathway fluxes. Comp Biochem Physiol A Mol Integr Physiol 2012; 163:22-9. [PMID: 22561667 DOI: 10.1016/j.cbpa.2012.04.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 04/19/2012] [Accepted: 04/24/2012] [Indexed: 11/22/2022]
Abstract
Hepatic glycogen synthesis fluxes from direct and indirect pathways were quantified in seabass by postmortem (2)H NMR analysis of plasma water (PW) and glycogen glucosyl (2)H enrichments from (2)H-enriched seawater. Eighteen fish (28.0 ± 1.7 cm and 218.0 ± 43.0 g) were divided into three groups of 6 and studied over 24 days with transfer to 5% (2)H-seawater after day 21. Over this period, one group was fed daily with fishmeal, a second group was fasted, and a third group was fasted for 21 days followed by 3 days refeeding. Glycogen turnover and sources were determined from the ratio of glucosyl position 5 enrichment to that of plasma water (H5/PW). Glycogen levels of fed fish were significantly higher than fasted (665.4 ± 345.2 μmol.g(-1) liver versus 77.2 ± 59.5 μmol.g(-1) liver, P<0.05) while refed fish had comparable levels to fed (584.6 ± 140.4 μmol.g(-1) liver). Glycogen enrichment of fed fish was undetectable indicating negligible turnover over 3 days. For fasted fish, H5/PW was ~50% indicating that half of the glycogen had turned over via indirect pathway flux. For refed fish, H5/PW was ~100% indicating that the indirect pathway accounted for all net glycogen synthesis. Direct pathway conversion of dietary carbohydrate to glycogen was not detected in any of the groups.
Collapse
|
11
|
Delgado TC, Barosa C, Nunes PM, Cerdán S, Geraldes CFGC, Jones JG. Resolving the sources of plasma glucose excursions following a glucose tolerance test in the rat with deuterated water and [U-13C]glucose. PLoS One 2012; 7:e34042. [PMID: 22479514 PMCID: PMC3316706 DOI: 10.1371/journal.pone.0034042] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 02/22/2012] [Indexed: 11/18/2022] Open
Abstract
Sources of plasma glucose excursions (PGE) following a glucose tolerance test enriched with [U-13C]glucose and deuterated water were directly resolved by 13C and 2H Nuclear Magnetic Resonance spectroscopy analysis of plasma glucose and water enrichments in rat. Plasma water 2H-enrichment attained isotopic steady-state within 2–4 minutes following the load. The fraction of PGE derived from endogenous sources was determined from the ratio of plasma glucose position 2 and plasma water 2H-enrichments. The fractional gluconeogenic contributions to PGE were obtained from plasma glucose positions 2 and 5 2H-positional enrichment ratios and load contributions were estimated from plasma [U-13C]glucose enrichments. At 15 minutes, the load contributed 26±5% of PGE while 14±2% originated from gluconeogenesis in healthy control rats. Between 15 and 120 minutes, the load contribution fell whereas the gluconeogenic contribution remained constant. High-fat fed animals had significant higher 120-minute blood glucose (173±6 mg/dL vs. 139±10 mg/dL, p<0.05) and gluconeogenic contributions to PGE (59±5 mg/dL vs. 38±3 mg/dL, p<0.01) relative to standard chow-fed controls. In summary, the endogenous and load components of PGE can be resolved during a glucose tolerance test and these measurements revealed that plasma glucose synthesis via gluconeogenesis remained active during the period immediately following a glucose load. In rats that were placed on high-fat diet, the development of glucose intolerance was associated with a significantly higher gluconeogenic contribution to plasma glucose levels after the load.
Collapse
Affiliation(s)
- Teresa C. Delgado
- Intermediary Metabolism Group and Inorganic Biochemistry and Molecular Imaging Group, Center for Neurosciences and Cell Biology, Coimbra, Portugal
- Laboratory for Imaging and Spectroscopy by Magnetic Resonance, Instituto de Investigaciones Biomédicas de Madrid Alberto Sols CSIC/UAM, Madrid, Spain
| | - Cristina Barosa
- Intermediary Metabolism Group and Inorganic Biochemistry and Molecular Imaging Group, Center for Neurosciences and Cell Biology, Coimbra, Portugal
| | - Patrícia M. Nunes
- Intermediary Metabolism Group and Inorganic Biochemistry and Molecular Imaging Group, Center for Neurosciences and Cell Biology, Coimbra, Portugal
| | - Sebastián Cerdán
- Laboratory for Imaging and Spectroscopy by Magnetic Resonance, Instituto de Investigaciones Biomédicas de Madrid Alberto Sols CSIC/UAM, Madrid, Spain
| | - Carlos F. G. C. Geraldes
- Intermediary Metabolism Group and Inorganic Biochemistry and Molecular Imaging Group, Center for Neurosciences and Cell Biology, Coimbra, Portugal
| | - John G. Jones
- Intermediary Metabolism Group and Inorganic Biochemistry and Molecular Imaging Group, Center for Neurosciences and Cell Biology, Coimbra, Portugal
- * E-mail:
| |
Collapse
|
12
|
Barosa C, Silva C, Fagulha A, Barros L, Caldeira MM, Carvalheiro M, Jones JG. Sources of hepatic glycogen synthesis following a milk-containing breakfast meal in healthy subjects. Metabolism 2012; 61:250-4. [PMID: 21862086 DOI: 10.1016/j.metabol.2011.06.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Revised: 06/08/2011] [Accepted: 06/26/2011] [Indexed: 11/20/2022]
Abstract
During feeding, dietary galactose is a potential source of hepatic glycogen synthesis; but its contribution has not been measured to date. In the presence of deuterated water ((2)H(2)O), uridine diphosphate (UDP)-glucose derived from galactose is not enriched, whereas the remainder derived from glucose-6-phosphate (G6P) is enriched in position 2 to the same level as body water, assuming complete G6P-fructose-6-phosphate (F6P) exchange. Hence, the difference between UDP-glucose position 2 and body water enrichments reflects the contribution of galactose to glycogen synthesis relative to all other sources. In study 1, G6P-F6P exchange in 6 healthy subjects was quantified by supplementing a milk-containing breakfast meal with 10 g of [U-(2)H(7)]glucose and quantifying the depletion of position 2 enrichment in urinary menthol glucuronide. In study 2, another 6 subjects ingested (2)H(2)O and acetaminophen followed by an identical breakfast meal with 10 g of [1-(13)C]glucose to resolve direct/indirect pathways and galactose contributions to glycogen synthesis. Metabolite enrichments were determined by (2)H and (13)C nuclear magnetic resonance. In study 1, G6P-F6P exchange approached completion; therefore, the difference between position 2 and body water enrichments in study 2 (0.20% ± 0.03% vs 0.27% ± 0.03%, P < .005) was attributed to galactose glycogenesis. Dietary galactose contributed 19% ± 3% to glycogen synthesis. Of the remainder, 58% ± 5% was derived from the direct pathway and 22% ± 4% via the indirect pathway. The contribution of galactose to hepatic glycogen synthesis was resolved from that of direct and indirect pathways using a combination of (2)H(2)O and [1-(13)C]glucose tracers.
Collapse
Affiliation(s)
- Cristina Barosa
- Biophysics and Biomedical NMR, Center for Neurosciences and Cell Biology, University of Coimbra, 3001-401 Coimbra, Portugal
| | | | | | | | | | | | | |
Collapse
|