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Coelho M, Mahar R, Belew GD, Torres A, Barosa C, Cabral F, Viegas I, Gastaldelli A, Mendes VM, Manadas B, Jones JG, Merritt ME. Enrichment of hepatic glycogen and plasma glucose from H₂ 18 O informs gluconeogenic and indirect pathway fluxes in naturally feeding mice. NMR IN BIOMEDICINE 2023; 36:e4837. [PMID: 36151589 PMCID: PMC9845176 DOI: 10.1002/nbm.4837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/22/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
Deuterated water (2 H2 O) is a widely used tracer of carbohydrate biosynthesis in both preclinical and clinical settings, but the significant kinetic isotope effects (KIE) of 2 H can distort metabolic information and mediate toxicity. 18 O-water (H2 18 O) has no significant KIE and is incorporated into specific carbohydrate oxygens via well-defined mechanisms, but to date it has not been evaluated in any animal model. Mice were given H2 18 O during overnight feeding and 18 O-enrichments of liver glycogen, triglyceride glycerol (TG), and blood glucose were quantified by 13 C NMR and mass spectrometry (MS). Enrichment of oxygens 5 and 6 relative to body water informed indirect pathway contributions from the Krebs cycle and triose phosphate sources. Compared with mice fed normal chow (NC), mice whose NC was supplemented with a fructose/glucose mix (i.e., a high sugar [HS] diet) had significantly higher indirect pathway contributions from triose phosphate sources, consistent with fructose glycogenesis. Blood glucose and liver TG 18 O-enrichments were quantified by MS. Blood glucose 18 O-enrichment was significantly higher for HS versus NC mice and was consistent with gluconeogenic fructose metabolism. TG 18 O-enrichment was extensive for both NC and HS mice, indicating a high turnover of liver triglyceride, independent of diet. Thus H2 18 O informs hepatic carbohydrate biosynthesis in similar detail to 2 H2 O but without KIE-associated risks.
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Affiliation(s)
- Margarida Coelho
- CNC ‐ Center for Neurosciences and Cell BiologyUniversity of CoimbraCoimbraPortugal
- Department of Chemistry, Faculty of Sciences and TechnologyUniversity of CoimbraCoimbraPortugal
| | - Rohit Mahar
- Department of Biochemistry and Molecular BiologyUniversity of FloridaGainesvilleFloridaUSA
| | - Getachew D. Belew
- CNC ‐ Center for Neurosciences and Cell BiologyUniversity of CoimbraCoimbraPortugal
| | - Alejandra Torres
- CNC ‐ Center for Neurosciences and Cell BiologyUniversity of CoimbraCoimbraPortugal
| | - Cristina Barosa
- CNC ‐ Center for Neurosciences and Cell BiologyUniversity of CoimbraCoimbraPortugal
| | - Fernando Cabral
- CNC ‐ Center for Neurosciences and Cell BiologyUniversity of CoimbraCoimbraPortugal
| | - Ivan Viegas
- Center for Functional Ecology, Department of Life SciencesUniversity of CoimbraCoimbraPortugal
| | | | - Vera M. Mendes
- CNC ‐ Center for Neurosciences and Cell BiologyUniversity of CoimbraCoimbraPortugal
| | - Bruno Manadas
- CNC ‐ Center for Neurosciences and Cell BiologyUniversity of CoimbraCoimbraPortugal
| | - John G. Jones
- CNC ‐ Center for Neurosciences and Cell BiologyUniversity of CoimbraCoimbraPortugal
| | - Matthew E. Merritt
- Department of Biochemistry and Molecular BiologyUniversity of FloridaGainesvilleFloridaUSA
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Deja S, Fu X, Fletcher JA, Kucejova B, Browning JD, Young JD, Burgess SC. Simultaneous tracers and a unified model of positional and mass isotopomers for quantification of metabolic flux in liver. Metab Eng 2019; 59:1-14. [PMID: 31891762 DOI: 10.1016/j.ymben.2019.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 12/12/2019] [Accepted: 12/21/2019] [Indexed: 12/23/2022]
Abstract
Computational models based on the metabolism of stable isotope tracers can yield valuable insight into the metabolic basis of disease. The complexity of these models is limited by the number of tracers and the ability to characterize tracer labeling in downstream metabolites. NMR spectroscopy is ideal for multiple tracer experiments since it precisely detects the position of tracer nuclei in molecules, but it lacks sensitivity for detecting low-concentration metabolites. GC-MS detects stable isotope mass enrichment in low-concentration metabolites, but lacks nuclei and positional specificity. We performed liver perfusions and in vivo infusions of 2H and 13C tracers, yielding complex glucose isotopomers that were assigned by NMR and fit to a newly developed metabolic model. Fluxes regressed from 2H and 13C NMR positional isotopomer enrichments served to validate GC-MS-based flux estimates obtained from the same experimental samples. NMR-derived fluxes were largely recapitulated by modeling the mass isotopomer distributions of six glucose fragment ions measured by GC-MS. Modest differences related to limited fragmentation coverage of glucose C1-C3 were identified, but fluxes such as gluconeogenesis, glycogenolysis, cataplerosis and TCA cycle flux were tightly correlated between the methods. Most importantly, modeling of GC-MS data could assign fluxes in primary mouse hepatocytes, an experiment that is impractical by 2H or 13C NMR.
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Affiliation(s)
- Stanislaw Deja
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Xiaorong Fu
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Justin A Fletcher
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Blanka Kucejova
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Jeffrey D Browning
- Department of Clinical Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Jamey D Young
- Department of Chemical and Biomolecular Engineering, Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37235, USA.
| | - Shawn C Burgess
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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Jin ES, Sherry AD, Malloy CR. Evidence for transaldolase activity in the isolated heart supplied with [U-13C3]glycerol. J Biol Chem 2012; 288:2914-22. [PMID: 23235149 DOI: 10.1074/jbc.m112.409441] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Studies of glycerol metabolism in the heart have largely emphasized its role in triglyceride synthesis. However, glycerol may also be oxidized in the citric acid cycle, and glycogen synthesis from glycerol has been reported in the nonmammalian myocardium. The intent of this study was to test the hypothesis that glycerol may be metabolized to glycogen in mammalian heart. Isolated rat hearts were supplied with a mixture of substrates including glucose, lactate, pyruvate, octanoate, [U-(13)C(3)]glycerol, and (2)H(2)O to probe various metabolic pathways including glycerol oxidation, glycolysis, the pentose phosphate pathway, and carbon sources of stored glycogen. NMR analysis confirmed that glycogen production from the level of the citric acid cycle did not occur and that the glycerol contribution to oxidation in the citric acid cycle was negligible in the presence of alternative substrates. Quite unexpectedly, (13)C from [U-(13)C(3)]glycerol appeared in glycogen in carbon positions 4-6 of glucosyl units but none in positions 1-3. The extent of [4,5,6-(13)C(3)]glucosyl unit enrichment in glycogen was enhanced by insulin but decreased by H(2)O(2). Given that triose phosphate isomerase is generally assumed to fully equilibrate carbon tracers in the triose pool, the marked (13)C asymmetry in glycogen can only be attributed to conversion of [U-(13)C(3)]glycerol to [U-(13)C(3)]dihydroxyacetone phosphate and [U-(13)C(3)]glyceraldehyde 3-phosphate followed by rearrangements in the nonoxidative branch of the pentose phosphate pathway involving transaldolase that places this (13)C-enriched 3-carbon unit only in the bottom half of hexose phosphate molecules contributing to glycogen.
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Affiliation(s)
- Eunsook S Jin
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
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Champagne CD, Houser DS, Fowler MA, Costa DP, Crocker DE. Gluconeogenesis is associated with high rates of tricarboxylic acid and pyruvate cycling in fasting northern elephant seals. Am J Physiol Regul Integr Comp Physiol 2012; 303:R340-52. [PMID: 22673783 DOI: 10.1152/ajpregu.00042.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Animals that endure prolonged periods of food deprivation preserve vital organ function by sparing protein from catabolism. Much of this protein sparing is achieved by reducing metabolic rate and suppressing gluconeogenesis while fasting. Northern elephant seals (Mirounga angustirostris) endure prolonged fasts of up to 3 mo at multiple life stages. During these fasts, elephant seals maintain high levels of activity and energy expenditure associated with breeding, reproduction, lactation, and development while maintaining rates of glucose production typical of a postabsorptive mammal. Therefore, we investigated how fasting elephant seals meet the requirements of glucose-dependent tissues while suppressing protein catabolism by measuring the contribution of glycogenolysis, glycerol, and phosphoenolpyruvate (PEP) to endogenous glucose production (EGP) during their natural 2-mo postweaning fast. Additionally, pathway flux rates associated with the tricarboxylic acid (TCA) cycle were measured specifically, flux through phosphoenolpyruvate carboxykinase (PEPCK) and pyruvate cycling. The rate of glucose production decreased during the fast (F(1,13) = 5.7, P = 0.04) but remained similar to that of postabsorptive mammals. The fractional contributions of glycogen, glycerol, and PEP did not change with fasting; PEP was the primary gluconeogenic precursor and accounted for ∼95% of EGP. This large contribution of PEP to glucose production occurred without substantial protein loss. Fluxes through the TCA cycle, PEPCK, and pyruvate cycling were higher than reported in other species and were the most energetically costly component of hepatic carbohydrate metabolism. The active pyruvate recycling fluxes detected in elephant seals may serve to rectify gluconeogeneic PEP production during restricted anaplerotic inflow in these fasting-adapted animals.
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Affiliation(s)
- Cory D Champagne
- Department of Ecology & Evolutionary Biology, University of California, Santa Cruz, USA.
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Woitiski CB, Neufeld RJ, Soares AF, Figueiredo IV, Veiga FJ, Carvalho RA. Evaluation of hepatic glucose metabolism via gluconeogenesis and glycogenolysis after oral administration of insulin nanoparticles. Drug Dev Ind Pharm 2012; 38:1441-50. [DOI: 10.3109/03639045.2011.653789] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Reis CP, Neufeld R, Veiga F, Figueiredo IV, Jones J, Soares AF, Nunes P, Damgé C, Carvalho RA. Effects of an oral insulin nanoparticle administration on hepatic glucose metabolism assessed by13C and2H isotopomer analysis. J Microencapsul 2011; 29:167-76. [DOI: 10.3109/02652048.2011.638992] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Junghans P, Görs S, Lang IS, Steinhoff J, Hammon HM, Metges CC. A simplified mass isotopomer approach to estimate gluconeogenesis rate in vivo using deuterium oxide. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:1287-95. [PMID: 20391600 DOI: 10.1002/rcm.4509] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We compare a new simplified (2)H enrichment mass isotopomer analysis (MIA) against the laborious hexamethylentetramine (HMT) method to quantify the contribution of gluconeogenesis (GNG) to total glucose production (GP) in calves. Both methods are based on the (2)H labeling of glucose after in vivo administration of deuterium oxide. The (2)H enrichments of plasma glucose at different C-H positions were measured as aldonitrile pentaacetate (AAc) and methyloxime-trimethylsilyl (MoxTMS) derivatives or HMT by gas chromatography/mass spectrometry (GC/MS). Two pre-ruminating fasted Holstein calves (51 kg body mass, BM, age 7 days) received two oral bolus doses of (2)H(2)O (10 g/kg BM, 70 atom% (2)H) at 7:00 h and 11:00 h after overnight food withdrawal. Blood samples for fractional GNG determination were collected at -24 and between 6 and 9 h after the first (2)H(2)O dose. The ratio of (2)H enrichments C5/C2 represents the contribution of GNG to GP. The (2)H enrichment at C2 was calculated based on the ion fragments at m/z 328 (C1-C6) - m/z 187 (C3-C6) of glucose AAc. The (2)H enrichment at C5 was approximated either by averaging the (2)H enrichment at C5-C6 using the ion fragment of glucose MoxTMS at m/z 205 or by conversion of the C5 of glucose into HMT. The fractional GNG calculated by the C5-C6 average (2)H enrichment method (41.4 +/- 6.9%) compared to the HMT method (34.3 +/- 11.4%) was not different (mean +/- SD, n = 6 replicates). In conclusion, GNG can be estimated with less laborious sample preparation by means of our new C5-C6 average (2)H enrichment method using AAc and MoxTMS glucose derivatives.
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Affiliation(s)
- Peter Junghans
- Leibniz Institute for Farm Animal Biology (FBN), Research Unit Nutritional Physiology 'Oskar Kellner', Wilhelm-Stahl-Allee 2, D-18196 Dummerstorf, Germany.
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Chacko SK, Sunehag AL, Sharma S, Sauer PJJ, Haymond MW. Reply to Burgess, Chandramouli, Browning, Schumann, and Previs. J Appl Physiol (1985) 2008. [DOI: 10.1152/japplphysiol.90521.2008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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9
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Zijlmans WCWR, van Kempen AAMW, Ackermans MT, de Metz J, Kager PA, Sauerwein HP. Very young children with uncomplicated falciparum malaria have higher risk of hypoglycaemia: a study from Suriname. Trop Med Int Health 2008; 13:626-34. [PMID: 18384481 DOI: 10.1111/j.1365-3156.2008.02064.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To measure glucose kinetics and the influence of age, nutritional status and fasting duration in children with uncomplicated falciparum malaria (UFM) under the age of 5 years. METHODS Plasma glucose concentration, endogenous glucose production (EGP) and gluconeogenesis (GNG) were measured using [6,6-(2)H(2)]glucose and (2)H(2)O in 17 very young (<3 years) and 7 older (3-5 years) Surinamese children with UFM admitted to the Distrikt Hospital Stoelmanseiland and Diakonessen Hospital Paramaribo over 17 months. RESULTS Plasma glucose concentration was lower in the group of very young children than in the older children (P = 0.028). There were no differences in EGP and GNG between the groups. Overall GNG contributed 56% (median, range 17-87%) to EGP, with no differences between the groups (P = 0.240). Glucose clearance was lower in the older children (P = 0.026). Glucose concentration did not differ between children with weight for length/height less than -1.3 SD and children with weight for length/height greater than -1.3 SD (P = 0.266). Plasma glucose concentration was not predicted by fasting duration (P = 0.762). CONCLUSIONS Our data suggest a higher risk of hypoglycaemia in very young children with uncomplicated malaria as plasma glucose concentration was lower in this study group. Since this could not be attributed to an impaired EGP, and because glucose clearance was lower in the older children, we presume that older children were better capable of reducing glucose utilization during fasting. Studies on glucose kinetics are feasible in very young children with malaria and give more insight in the pathophysiology of hypoglycaemia.
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Bock G, Schumann WC, Basu R, Burgess SC, Yan Z, Chandramouli V, Rizza RA, Landau BR. Evidence that processes other than gluconeogenesis may influence the ratio of deuterium on the fifth and third carbons of glucose: implications for the use of 2H2O to measure gluconeogenesis in humans. Diabetes 2008; 57:50-5. [PMID: 17934142 DOI: 10.2337/db07-0694] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The deuterated water method uses the ratio of deuterium on carbons 5 and 2 (C5/C2) or 3 and 2 (C3/C2) to estimate the fraction of glucose derived from gluconeogenesis. The current studies determined whether C3 and C5 glucose enrichment is influenced by processes other than gluconeogenesis. RESEARCH DESIGN AND METHODS Six nondiabetic subjects were infused with [3,5-(2)H(2)]glucose and insulin while glucose was clamped at approximately 5 mmol/l; the C5-to-C3 ratio was measured in the in UDP-glucose pool using nuclear magnetic resonance and the acetaminophen glucuronide method. RESULTS Whereas the C5-to-C3 ratio of the infusate was 1.07, the ratio in UDP-glucose was <1.0 in all subjects both before (0.75 +/- 0.07) and during (0.67 +/- 0.05) the insulin infusion. CONCLUSIONS These data indicate that the deuterium on C5 of glucose is lost more rapidly relative to the deuterium on C3. The decrease in the C5-to-C3 ratio could result from exchange of the lower three carbons of fructose-6-phosphate with unlabeled three-carbon precursors via the transaldolase reaction and/or selective retention of the C3 deuterium at the level of triosephosphate isomerase due to a kinetic isotope effect. After ingestion of (2)H(2)O, these processes would increase the enrichment of C5 and decrease the enrichment of C3, respectively, with the former causing an overestimation of gluconeogenesis using the C2-to-C5 ratio and the latter an underestimation using the C3-to-C2 ratio. Future studies will be required to determine whether the impact of these processes on the measurement of gluconeogenesis differs among the disease states being evaluated (e.g., diabetes or obesity).
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Affiliation(s)
- Gerlies Bock
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Department of Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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11
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Sena CM, Barosa C, Nunes E, Seiça R, Jones JG. Sources of endogenous glucose production in the Goto–Kakizaki diabetic rat. DIABETES & METABOLISM 2007; 33:296-302. [PMID: 17553720 DOI: 10.1016/j.diabet.2007.03.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Accepted: 03/18/2007] [Indexed: 10/23/2022]
Abstract
Plasma glucose, insulin and glucose tolerance were quantified in diabetic Goto-Kakizaki (GK) rats (342+/-45 g, n = 5) and compared with weight-matched non-diabetic Wistars (307+/-30 g, n = 8). Compared to Wistars, GK rats had higher fasting plasma insulin (219+/-50 versus 44+/-14 pmol/l, P<0.002) and glucose (9.2+/-2.3 versus 5.5+/-0.5 mmol/l, P<0.025). GK rats showed impaired glucose tolerance (IPGTT 2 h plasma glucose=14+/-1.5 versus 6.4+/-0.1 mmol/l, P<0.001). Endogenous glucose production (EGP) from glycogenolysis, phosphoenolpyruvate (PEP) and glycerol after 6 hours of fasting was quantified by a primed infusion of [U-(13)C]glucose and (2)H(2)O tracers and (2)H/(13)C NMR analysis of plasma glucose. EGP was higher in GK compared to Wistar rats (191+/-16 versus 104+/-27 mumol/kg per min, P<0.005). This was sustained by increased gluconeogenesis from PEP (85+/-12 versus 35+/-4 mumol/kg per min, P<0.02). Gluconeogenesis from glycerol was not different (20+/-3 in Wistar versus 30+/-6 mumol/kg per min for GK), and glycogenolysis fluxes were also not significantly different (76+/-23 mumol/kg per min for GK versus 52+/-19 mumol/kg per min for Wistar). The Cori cycle accounted for most of PEP gluconeogenesis in both Wistar and GK rats (85+/-15% and 77+/-10%, respectively). Therefore, increased gluconeogenesis in GK rats is largely sustained by increased Cori cycling while the maintenance of glycogenolysis indicates a failure in hepatic autoregulation of EGP.
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Affiliation(s)
- C M Sena
- Institute of Physiology, Faculty of Medicine, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal.
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Chevalier S, Burgess SC, Malloy CR, Gougeon R, Marliss EB, Morais JA. The greater contribution of gluconeogenesis to glucose production in obesity is related to increased whole-body protein catabolism. Diabetes 2006; 55:675-81. [PMID: 16505230 DOI: 10.2337/diabetes.55.03.06.db05-1117] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Obesity is associated with an increase in the fractional contribution of gluconeogenesis (GNG) to glucose production. We tested if this was related to the altered protein metabolism in obesity. GNG(PEP) (via phosphoenol pyruvate [PEP]) was measured after a 17-h fast using the deuterated water method and 2H nuclear magnetic resonance spectroscopy of plasma glucose. Whole-body 13C-leucine and 3H-glucose kinetics were measured in the postabsorptive state and during a hyperinsulinemic-euglycemic-isoaminoacidemic clamp in 19 (10 men and 9 women) lean and 16 (7 men and 9 women) obese nondiabetic subjects. Endogenous glucose production was not different between groups. Postabsorptive %GNG(PEP) and GNG(PEP) flux were higher in obese subjects, and glycogenolysis contributed less to glucose production than in lean subjects. GNG(PEP) flux correlated with all indexes of adiposity and with postabsorptive leucine rate of appearance (Ra) (protein catabolism). GNG(PEP) was negatively related to the clamp glucose rate of disposal (Rd) and to the protein anabolic response to hyperinsulinemia. In conclusion, the increased contribution of GNG to glucose production in obesity is linked to increased postabsorptive protein catabolism and insulin resistance of both glucose and protein metabolism. Due to increased protein turnover rates, greater supply of gluconeogenic amino acids to the liver may trigger their preferential use over glycogen for glucose production.
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Affiliation(s)
- Stéphanie Chevalier
- McGill Nutrition and Food Science Centre, McGill University Health Centre, Royal Victoria Hospital, 687 Pine Ave. West, Montreal, Quebec, Canada, H3A 1A1
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Kunert O, Stingl H, Rosian E, Krssák M, Bernroider E, Seebacher W, Zangger K, Staehr P, Chandramouli V, Landau BR, Nowotny P, Waldhäusl W, Haslinger E, Roden M. Measurement of fractional whole-body gluconeogenesis in humans from blood samples using 2H nuclear magnetic resonance spectroscopy. Diabetes 2003; 52:2475-82. [PMID: 14514629 DOI: 10.2337/diabetes.52.10.2475] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Several problems limit quantification of gluconeogenesis. We applied in vitro 2H-nuclear magnetic resonance (NMR) spectroscopy to simultaneously measure 2H in all glucose carbons for direct assessment of gluconeogenesis. This method was compared with 2H measurement in carbons 5 and 2 using gas chromatography-mass spectrometry (hexamethylenetetramine [HMT]) and with in vivo 13C magnetic resonance spectroscopy (MRS). After 14 h of fasting, and following 2H2O ingestion, blood was obtained from nine healthy and seven type 2 diabetic subjects. Glucose was purified, acetylated, and analyzed for 2H in carbons 1-6 with 2H-NMR. Using 5:2 ratios, gluconeogenesis increased (P < 0.05) over time and mean gluconeogenesis was lower in control subjects than in type 2 diabetic patients (63 +/- 3 vs. 75 +/- 2%, P < 0.01). 13C-MRS revealed higher hepatic glycogenolysis in control subjects (3.9 +/- 0.4 vs. 2.3 +/- 0.2 micromol.kg(-1).min(-1)) yielding mean contribution of gluconeogenesis of 65 +/- 3 and 77 +/- 2% (P < 0.005). Measurement of gluconeogenesis by 2H-NMR correlated linearly with 13C-MRS (r = 0.758, P = 0.0007) and HMT (r = 0.759, P = 0.0007). In an additional protocol, 2H enrichments demonstrated a fast decline of gluconeogenesis from approximately 100 to approximately 68% (P < 0.02) within 4 h of galactose infusion after 40-44 h of fasting. Thus, in vitro 2H-NMR offers an alternative approach to determine fractional gluconeogenesis in good agreement with standard methods and allows monitoring of rapid metabolic alterations.
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Affiliation(s)
- O Kunert
- Department of Pharmaceutical Chemistry, University of Graz, Graz, Austria
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14
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Merritt M, Bretthorst GL, Burgess SC, Sherry AD, Malloy CR. Sources of plasma glucose by automated bayesian analysis of2H NMR spectra. Magn Reson Med 2003; 50:659-63. [PMID: 14523948 DOI: 10.1002/mrm.10577] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Sources of blood glucose can be determined after oral ingestion of (2)H(2)O followed by isolation of plasma glucose and measurement of the relative (2)H enrichments in select positions within the glucose molecule. Typically, (2)H enrichments are obtained by mass spectrometry but (2)H NMR offers an alternative. Here it is demonstrated that the entire analysis may be automated by Bayesian analysis of a (2)H free induction decay signal of monoacetone glucose to obtain a direct readout of the relative contributions of glycogenolysis, glycerol, and phosphoenol pyruvate to plasma glucose production. Furthermore, Markov Chain Monte Carlo (MCMC) simulations of the posterior probability density provide uncertainties in all metabolic parameters from a single patient, thereby allowing comparisons in glucose metabolism from one individual to another. The combined MCMC Bayesian methodology is operationally simple and requires little intervention from the operator.
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Affiliation(s)
- Matthew Merritt
- Department of Radiology, The Mary Nell and Ralph B. Rogers Magnetic Resonance Center, University of Texas Southwestern Medical Center, Dallas, Texas 75235-9085, USA.
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15
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Burgess SC, Nuss M, Chandramouli V, Hardin DS, Rice M, Landau BR, Malloy CR, Sherry AD. Analysis of gluconeogenic pathways in vivo by distribution of 2H in plasma glucose: comparison of nuclear magnetic resonance and mass spectrometry. Anal Biochem 2003; 318:321-4. [PMID: 12814639 DOI: 10.1016/s0003-2697(03)00158-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Shawn C Burgess
- The Mary Nell and Ralph B. Rogers Magnetic Resonance Center, Department of Radiology, University of Texas Southwestern Medical Center, 5801 Forest Park Road, Dallas, TX 75235-9085, USA.
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16
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Carvalho RA, Jones JG, McGuirk C, Sherry AD, Malloy CR. Hepatic gluconeogenesis and Krebs cycle fluxes in a CCl4 model of acute liver failure. NMR IN BIOMEDICINE 2002; 15:45-51. [PMID: 11840552 DOI: 10.1002/nbm.745] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Acute liver failure was induced in rats by CCl4 administration and its effects on the hepatic Krebs cycle and gluconeogenic fluxes were evaluated in situ by 13C NMR isotopomer analysis of hepatic glucose following infusion of [U-13C]propionate. In fed animals, CCl4 injury caused a significant increase in relative gluconeogenic flux from 0.80+/-0.10 to 1.34 +/-0.24 times the flux through citrate synthase (p<0.01). In 24-h fasted animals, CCl4-injury also significantly increased relative gluconeogenic flux from 1.36+/-0.16 to 1.80+/-0.22 times the flux through citrate synthase (p<0.01). Recycling of PEP via pyruvate and oxaloacetate was extensive under all conditions and was not significantly altered by CCl4 injury. CCl4 injury significantly reduced hepatic glucose output by 26% (42.8+/-7.3 vs 58.1+/-2.4 micromol/kg/min, p=0.005), which was attributed to a 26% decrease in absolute gluconeogenic flux from PEP (85.6+/-14.6 vs 116+/-4.8 micromol/kg/min, p<0.01). These changes were accompanied by a 47% reduction in absolute citrate synthase flux (90.6+/-8.0 to 47.6+/-8.0 micromol/kg/min, p<0.005), indicating that oxidative Krebs cycle flux was more susceptible to CCl4 injury. The reduction in absolute fluxes indicate a significant loss of hepatic metabolic capacity, while the significant increases in relative gluconeogenic fluxes suggest a reorganization of metabolic activity towards preserving hepatic glucose output.
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Affiliation(s)
- Rui A Carvalho
- Department of Biochemistry and Center of Neurosciences, University of Coimbra, Portugal.
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Jones JG, Solomon MA, Cole SM, Sherry AD, Malloy CR. An integrated (2)H and (13)C NMR study of gluconeogenesis and TCA cycle flux in humans. Am J Physiol Endocrinol Metab 2001; 281:E848-56. [PMID: 11551863 DOI: 10.1152/ajpendo.2001.281.4.e848] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hepatic glucose synthesis from glycogen, glycerol, and the tricarboxylic acid (TCA) cycle was measured in five overnight-fasted subjects by (1)H, (2)H, and (13)C NMR analysis of blood glucose, urinary acetaminophen glucuronide, and urinary phenylacetylglutamine after administration of [1,6-(13)C(2)]glucose, (2)H(2)O, and [U-(13)C(3)]propionate. This combination of tracers allows three separate elements of hepatic glucose production (GP) to be probed simultaneously in a single study: 1) endogenous GP, 2) the contribution of glycogen, phosphoenolpyruvate (PEP), and glycerol to GP, and 3) flux through PEP carboxykinase, pyruvate recycling, and the TCA cycle. Isotope-dilution measurements of [1,6-(13)C(2)] glucose by (1)H and (13)C NMR indicated that GP in 16-h-fasted humans was 10.7 +/- 0.9 micromol.kg(-1).min(-1). (2)H NMR spectra of monoacetone glucose (derived from plasma glucose) provided the relative (2)H enrichment at glucose H-2, H-5, and H-6S, which, in turn, reflects the contribution of glycogen, PEP, and glycerol to total GP (5.5 +/- 0.7, 4.8 +/- 1.0, and 0.4 +/- 0.3 micromol.kg(-1).min(-1), respectively). Interestingly, (13)C NMR isotopomer analysis of phenylacetylglutamine and acetaminophen glucuronide reported different values for PEP carboxykinase flux (68.8 +/- 9.8 vs. 37.5 +/- 7.9 micromol.kg(-1).min(-1)), PEP recycling flux (59.1 +/- 9.8 vs. 27.8 +/- 6.8 micromol.kg(-1).min(-1)), and TCA cycle flux (10.9 +/- 1.4 vs. 5.4 +/- 1.4 micromol.kg(-1).min(-1)). These differences may reflect zonation of propionate metabolism in the liver.
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Affiliation(s)
- J G Jones
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas 75235, USA
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