scholarly journals Estimating gluconeogenesis by NMR isotopomer distribution analysis of [13C]bicarbonate and [1-13C]lactate

2008 ◽  
Vol 21 (4) ◽  
pp. 337-344 ◽  
Author(s):  
Tiago Cardoso Alves ◽  
Patrícia Maria Nunes ◽  
Carlos Marques Palmeira ◽  
John Griffith Jones ◽  
Rui Albuquerque Carvalho
Keyword(s):  
Distribution Analysis ◽  
Isotopomer Distribution

13C-NMR isotopomer distribution analysis: a method for measuring metabolic fluxes in condensation biosynthesis

2002 ◽  
Vol 15 (6) ◽  
pp. 404-415 ◽  
Author(s):  
Caterina Puccetti ◽  
Tommaso Aureli ◽  
Cesare Manetti ◽  
Filippo Conti
Keyword(s):  
13C Nmr ◽  
Distribution Analysis ◽  
Isotopomer Distribution ◽  
Metabolic Fluxes

scholarly journals Software LS-MIDA for efficient mass isotopomer distribution analysis in metabolic modelling

2013 ◽  
Vol 14 (1) ◽  
pp. 218 ◽  
Author(s):  
Zeeshan Ahmed ◽  
Saman Zeeshan ◽  
Claudia Huber ◽  
Michael Hensel ◽  
Dietmar Schomburg ◽  
...  
Keyword(s):  
Distribution Analysis ◽  
Metabolic Modelling ◽  
Isotopomer Distribution ◽  
Mass Isotopomer Distribution Analysis ◽  
Mass Isotopomer

Measurement of gluconeogenesis in exercising men by mass isotopomer distribution analysis

2002 ◽  
Vol 93 (1) ◽  
pp. 233-241 ◽  
Author(s):  
Jeff K. Trimmer ◽  
Jean-Marc Schwarz ◽  
Gretchen A. Casazza ◽  
Michael A. Horning ◽  
Nestor Rodriguez ◽  
...  
Keyword(s):  
Rest Period ◽  
Glucose Production ◽  
Moderate Intensity ◽  
Dependent Manner ◽  
Distribution Analysis ◽  
Moderate Intensity Exercise ◽  
Isotopomer Distribution ◽  
Mass Isotopomer Distribution Analysis ◽  
The Difference ◽  
Mass Isotopomer

We evaluated the hypothesis that coordinated adjustments in absolute rates of gluconeogenesis (GNGab) and hepatic glycogenolysis (Gly) would maintain euglycemia and match glucose production (GP) to peripheral utilization during rest and exercise. Specifically, we evaluated the extent to which gradations in exercise power output would affect the contribution of GNGab to GP. For these purposes, we employed mass isotopomer distribution analysis (MIDA) and isotope-dilution techniques on eight postabsorptive (PA) endurance-trained men during 90 min of leg cycle ergometry at 45 and 65% peak O2 consumption (V˙o 2 peak; moderate and hard intensities, respectively) and the preceding rest period. GP was constant in resting subjects, whereas the fraction from GNG (fGNG) increased over time during rest (22.3 ± 0.9% at 11.25 h PA vs. 25.6 ± 0.9% at 12.0 h PA, P < 0.05). In the transition from rest to exercise, GP increased in an intensity-dependent manner (rest, 2.0 ± 0.1; 45%, 4.0 ± 0.4; 65%, 5.84 ± 0.64 mg · kg−1 · min−1, P < 0.05), although glucose rate of disappearance exceeded rate of appearance during the last 30 min of exercise at 65%V˙o 2 peak. Compared with rest, increases in GP were sustained by 92 and 135% increments in GNGab during moderate- and hard-intensity exercises, respectively. Correspondingly, Gly (calculated as the difference between GP and MIDA-measured GNGab) increased 100 and 203% over rest during the two exercise intensities. During moderate-intensity exercise, fGNG was the same as at rest; however, during the harder exercise fGNG decreased significantly to account for only 21% of GP. The highest sustained GNGab observed in these trials on PA men was 1.24 ± 0.3 mg · kg−1 · min−1. We conclude that, after an overnight fast, 1) absolute GNG rates increased with intensity of effort despite a reduced fGNG at 65% V˙o 2 peak, 2) during exercise Gly is more responsible than GNGab for maintaining GP, and 3) in 12-h fasted men, neither increased Gly or GNGab nor was their combination able to maintain euglycemia during prolonged hard (65%V˙o 2 peak) exercise.

Measuring gluconeogenesis with [2-13C]glycerol and mass isotopomer distribution analysis of glucose

1995 ◽  
Vol 269 (3) ◽  
pp. E516-E523 ◽  
Author(s):  
O. Peroni ◽  
V. Large ◽  
M. Beylot
Keyword(s):  
Glucose Production ◽  
Distribution Analysis ◽  
Isotopomer Distribution ◽  
Mass Isotopomer Distribution Analysis ◽  
Total Glucose ◽  
Glucose Output ◽  
Total Glycerol ◽  
Mass Isotopomer

We tested the validity of the use of [2-13C]glycerol and of the mass isotopomer distribution analysis of glucose for measuring gluconeogenesis in vitro and in vivo. When isolated rat livers (starved for 48 h) were infused with labeled glycerol without or with lactate+pyruvate, gluconeogenesis accounted for > 90% of glucose production. When glucose was added to the infusate so that glucose produced by the liver represented only 80 or 45% of total glucose output, this dilution could be calculated from the mass isotopomer distribution of glucose. When postabsorptive and starved rats were infused with [2-13C]glycerol, gluconeogenesis accounted for 54 +/- 2 and 89 +/- 1%, respectively, of glucose production. However, accurate measures could be obtained, particularly in postabsorptive rats, only with high tracer infusion rates (representing > or = 50% of endogenous glycerol production rate). In both groups of rats, these infusion rates resulted in an increase in total glycerol turnover rate and gluconeogenesis from glycerol. In addition, hepatic concentration of glycerol 3-phosphate was increased. In conclusion, [2-13C]glycerol infusion and mass isotopomer distribution analysis of glucose appear to be useful methods for studies of gluconeogenesis in vitro and in vivo; however, accurate measurements in vivo can be obtained only at the expense of some perturbation of the metabolic pathway studied.

Newly synthesized cholesterol in human bile and plasma: quantitation by mass isotopomer distribution analysis

1997 ◽  
Vol 272 (2) ◽  
pp. G367-G373 ◽  
Author(s):  
K. Empen ◽  
K. Lange ◽  
E. F. Stange ◽  
J. Scheibner
Keyword(s):  
De Novo ◽  
Charge Ratio ◽  
Gas Chromatography Mass Spectrometry ◽  
Distribution Analysis ◽  
Biliary Cholesterol ◽  
Human Bile ◽  
Isotopomer Distribution ◽  
Mass Isotopomer Distribution Analysis ◽  
Fractional Synthesis ◽  
Mass Isotopomer

The purpose of this study was to quantitate the contribution of newly synthesized cholesterol to bile and plasma in humans. Eight healthy volunteers were intravenously infused with 0.125 mmol of [1-(13)C]acetate per kilogram per hour for 15 h. During continuous enteral nutrition, plasma aliquots and samples of duodenal bile were collected hourly. The trimethysilylether of unesterified cholesterol was analyzed by gas chromatography-mass spectrometry for quantitation of the mass fragments M(+0) [mass-to-charge ratio (m/z) 368], M(+1) (m/z 369), M(+2) (m/z 370), M(+3) (m/z 371), and M(+4) (m/z 372). The fractional syntheses of plasma and biliary cholesterol were determined using mass isotopomer distribution analysis. After 6 h of infusion, the 13C enrichment of the acetate pool remained constant at 12%. The fractional synthesis increased continuously during [13C]acetate infusion and reached 4.2% and 5.3% in cholesterol of plasma and bile, respectively. Both were highly correlated, but the fractional synthesis of biliary cholesterol exceeded that of plasma (P < 0.05). It may be concluded that the contribution of de novo cholesterol synthesis to bile exceeds that to plasma but is minor in humans.

scholarly journals Limitations of the Mass Isotopomer Distribution Analysis of Glucose to Study Gluconeogenesis

1995 ◽  
Vol 270 (34) ◽  
pp. 19806-19815 ◽  
Author(s):  
Stephen F. Previs ◽  
Charles A. Fernandez ◽  
Dawei Yang ◽  
Maxim V. Soloviev ◽  
France David ◽  
...  
Keyword(s):  
Distribution Analysis ◽  
Isotopomer Distribution ◽  
Mass Isotopomer Distribution Analysis ◽  
Mass Isotopomer

scholarly journals Limitations of the Mass Isotopomer Distribution Analysis of Glucose to Study Gluconeogenesis

1998 ◽  
Vol 273 (27) ◽  
pp. 16853-16859 ◽  
Author(s):  
Stephen F. Previs ◽  
Peter T. Hallowell ◽  
Kevin D. Neimanis ◽  
France David ◽  
Henri Brunengraber
Keyword(s):  
Distribution Analysis ◽  
Isotopomer Distribution ◽  
Mass Isotopomer Distribution Analysis ◽  
Mass Isotopomer
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