Selected ion monitoring gas chromatography/mass spectrometry using uniformly labelled (13C)glucose for determination of glucose turnover in man

Pickert, A.; Overkamp, D.; Renn, W.; Liebich, H.M.; Eggstein, M.

doi:10.1002/bms.1200200408

Cited by 33 publications

(28 citation statements)

References 9 publications

(2 reference statements)

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“…Isotope tracer/ tracee ratio of [U- 13 C] palmitate was determined using GCcombustion IRMS (Finnigan MAT 252). Plasma glucose was first extracted with chloroform-methanol-water and derivatization was performed with butylboronic acid and acetic anhydride as described previously [27]. After derivatization, plasma [6,6-2 H 2 ] glucose enrichment was determined by electron ionization GC-MS (Finnigan INCOS-XL).…”

Section: Blood-and Breath-sample Analysismentioning

confidence: 99%

Carbohydrate Supplementation During Prolonged Cycling Exercise Spares Muscle Glycogen But Does Not Affect Intramyocellular Lipid Use.

Stellingwerff

Boon

Gijsen

et al. 2007

Medicine &Amp; Science in Sports &Amp; Exercise

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Using contemporary stable-isotope methodology and fluorescence microscopy, we assessed the impact of carbohydrate supplementation on whole-body and fibertype-specific intramyocellular triacylglycerol (IMTG) and glycogen use during prolonged endurance exercise. Ten endurance-trained male subjects were studied twice during 3 h of cycling at 63±4% of maximal O 2 uptake with either glucose ingestion (CHO trial; 0.7 g CHO kg −1 h −1 ) or without (CON placebo trial; water only). Continuous infusions with [U-13 C] palmitate and [6,6-2 H 2 ] glucose were applied to quantify plasma free fatty acids (FFA) and glucose oxidation rates and to estimate intramyocellular lipid and glycogen use. Before and after exercise, muscle biopsy samples were taken to quantify fiber-type-specific IMTG and glycogen content. Plasma glucose rate of appearance (R a ) and carbohydrate oxidation rates were substantially greater in the CHO vs CON trial. Carbohydrate supplementation resulted in a lower muscle glycogen use during the first hour of exercise in the CHO vs CON trial, resulting in a 38±19 and 57±22% decreased utilization in type I and II muscle-fiber glycogen content, respectively. In the CHO trial, both plasma FFA R a and subsequent plasma FFA concentrations were lower, resulting in a 34±12% reduction in plasma FFA oxidation rates during exercise (P<0.05). Carbohydrate intake did not augment IMTG utilization, as fluorescence microscopy revealed a 76 ± 21 and 78 ± 22% reduction in type I muscle-fiber lipid content in the CHO and CON trial, respectively. We conclude that carbohydrate supplementation during prolonged cycling exercise does not modulate IMTG use but spares muscle glycogen use during the initial stages of exercise in endurance-trained men.

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Section: Blood-and Breath-sample Analysismentioning

confidence: 99%

Carbohydrate Supplementation During Prolonged Cycling Exercise Spares Muscle Glycogen But Does Not Affect Intramyocellular Lipid Use.

Stellingwerff

Boon

Gijsen

et al. 2007

Medicine &Amp; Science in Sports &Amp; Exercise

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“…In both groups there was a significant uptake of 13 C-palmitate (slightly lower in type 2 diabetic subjects; P ϭ 0.06) and 13 C-glutamate. In control 12 C ratio ϫ concentration ϫ number of C-atoms) Ϫ (venous 13 C/ 12 C ratio ϫ concentration ϫ number of C-atoms)], with plasma blood flow in ml ⅐ 100 ml Ϫ1 tissue ⅐ min Ϫ1 and concentration in mol/l; see CALCULATIONS. subjects, there was significant 13 CO 2 release (15% of 13 C uptake from labeled palmitate) and a significant 13 Cglutamine release (release of 13 C-labeled atoms from glutamine was 6% of 13 C uptake from labeled palmitate; P Ͻ 0.05).…”

Section: Ratios) During [U-13 C]palmitate Infusion In Control (ⅺ) Amentioning

confidence: 99%

“…The resulting derivative contained 23 carbon atoms, 5 of which were from glutamine or glutamate; the 13 C/ 12 C ratio was therefore corrected by a factor of 23/5. To determine plasma glucose enrichment, glucose was extracted with chloroform-methanol-water, and derivatization occurred with butylboronic acid and acetic anhydride, as previously described (12). The resulting derivative contained 16 carbon atoms, 6 of which were from glucose; the 13 C/ 12 C ratio was therefore corrected by a factor of 16/6.…”

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confidence: 99%

The Fate of [U-13C]Palmitate Extracted by Skeletal Muscle in Subjects With Type 2 Diabetes and Control Subjects

Blaak

Wagenmakers

2002

Diabetes

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The current study investigated the fate of a [U-13 C] palmitate tracer extracted by forearm muscle in type 2 diabetic and control subjects. We studied seven healthy lean male subjects and seven obese male subjects with type 2 diabetes using the forearm muscle balance technique with continuous intravenous infusion of the stable isotope tracer [U-13 C]palmitate under baseline conditions and during intravenous infusion of the nonselective ␤-agonist isoprenaline (ISO; 20 ng ⅐ kg ؊1 lean body mass ⅐ min ؊1 ). In skeletal muscle of control subjects, there was a significant release of 13 C-labeled oxidation products in the form of 13 CO 2 (15% of 13 C uptake from labeled palmitate) and a significant release of 13 C-labeled glutamine (release of 13 C-labeled atoms from glutamine was 6% of 13 C uptake from labeled palmitate), whereas in type 2 diabetic subjects there was no detectable release of 13 CO 2 and 13 C-glutamine, despite a significant uptake of [U-13 C]palmitate (60% of control value). There was net uptake of arterial 13 Clabeled glutamate by forearm muscle in both groups. Also, the ISO-induced increase in arterial glutamine enrichment and arterial concentration of 13 C-glutamine was more pronounced in the diabetic group relative to control subjects. In view of the diminished ISO-induced release of 13 C-glutamine from type 2 diabetic muscle, the latter data indicate that more [U-13 C]palmitate entered the liver in the diabetic group and was incorporated into newly synthesized glutamine and glutamate molecules. Thus, the lack of release of 13 C-labeled oxidation products by type 2 diabetic muscle during ␤-adrenergic stimulation, despite significant [U-13 C]-palmitate uptake, indicates differences in the handling of fatty acids between type 2 diabetic subjects and healthy control subjects. Diabetes 51:784 -789, 2002

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“…Isotope tracerÏtracee ratio of palmitate was determined using GC-IRMS and corrected for the extra methyl group in its derivative. For determination of the plasma glucose tracerÏtracee ratio, the glucose was extracted with chloroformmethanol-water and derivatization occurred with butylboronic acid and acetic anhydride as described before (Pickert et al 1991). The resulting derivative contains sixteen carbon atoms of which six are labelled; TTR is therefore corrected by the factor 16Ï6.…”

Section: Sample Analysismentioning

confidence: 99%

Validation of the [1,2‐¹³C]acetate recovery factor for correction of [U‐¹³C]palmitate oxidation rates in humans

Schrauwen

Aggel-Leijssen

Lichtenbelt

et al. 1998

The Journal of Physiology

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The validity of estimations of plasma fatty acid oxidation using tracers has often been questioned. The appearance of isotopic markers in breath CO2 is delayed and incomplete. Recently suggestions have been made that substantial amounts of tracer are incorporated into products of the tricarboxylic acid cycle (e.g. glucose, glutamine and glutamate) and that an acetate correction factor can be used to correct for tracer fixation. In the present study we investigated whether the appearance of 13CO2 during a separate infusion of [1,2‐13C]acetate could be used for correction of [U‐13C]palmitate oxidation rates in studies lasting <2 h and we quantified the appearance of tracer in the glutamine, glutamate and glucose pools of the body. An infusion of either [1,2‐13C]acetate (0.104 μmol min−1 kg−1) or [U‐13C]palmitate (0.013 μmol min−1 kg−1) was given to eight male subjects and continued for 2 h at rest. In six subjects the infusion of [1,2‐13C]acetate was repeated to determine reproducibility of the acetate recovery. Fractional recovery in breath from [1,2‐13C]acetate gradually increased during the infusion period at rest from 14.1 ± 0.6 % at 60 min to 26.5 ± 0.5 % at 120 min after the start of the infusion. Intersubject coefficient of variance was 8.3 ± 0.6 % and intrasubject coefficient of variance of the acetate recovery tests was 4.0 ± 1.5 %. After 2 h of [1,2‐13C]acetate infusion, 12.4 ± 0.8 and 10.3 ± 0.9 % of infused 13C was incorporated in the glutamine and glutamate pools, respectively. In conclusion, the [1,2‐13C]acetate recovery factor can be used for correcting the rate of [U‐13C]palmitate oxidation in infusing studies of 2 h in resting conditions. Failure to use this recovery factor leads to a substantial underestimation of the rate of plasma free fatty acid oxidation. The extent of label fixation could largely be explained by accumulation of tracer carbon in glutamine and glutamate, and the accumulation in glucose is negligible.

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Selected ion monitoring gas chromatography/mass spectrometry using uniformly labelled (13C)glucose for determination of glucose turnover in man

Cited by 33 publications

References 9 publications

Carbohydrate Supplementation During Prolonged Cycling Exercise Spares Muscle Glycogen But Does Not Affect Intramyocellular Lipid Use.

Carbohydrate Supplementation During Prolonged Cycling Exercise Spares Muscle Glycogen But Does Not Affect Intramyocellular Lipid Use.

The Fate of [U-13C]Palmitate Extracted by Skeletal Muscle in Subjects With Type 2 Diabetes and Control Subjects

Validation of the [1,2‐¹³C]acetate recovery factor for correction of [U‐¹³C]palmitate oxidation rates in humans

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Selected ion monitoring gas chromatography/mass spectrometry using uniformly labelled (13C)glucose for determination of glucose turnover in man

Cited by 33 publications

References 9 publications

Carbohydrate Supplementation During Prolonged Cycling Exercise Spares Muscle Glycogen But Does Not Affect Intramyocellular Lipid Use.

Carbohydrate Supplementation During Prolonged Cycling Exercise Spares Muscle Glycogen But Does Not Affect Intramyocellular Lipid Use.

The Fate of [U-13C]Palmitate Extracted by Skeletal Muscle in Subjects With Type 2 Diabetes and Control Subjects

Validation of the [1,2‐13C]acetate recovery factor for correction of [U‐13C]palmitate oxidation rates in humans

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Validation of the [1,2‐¹³C]acetate recovery factor for correction of [U‐¹³C]palmitate oxidation rates in humans