Measurement of Fractional Whole-Body Gluconeogenesis in Humans From Blood Samples Using 2H Nuclear Magnetic Resonance Spectroscopy
- O. Kunert1,
- H. Stingl2,
- E. Rosian1,
- M. Krššák2,
- E. Bernroider2,
- W. Seebacher1,
- K. Zangger1,
- P. Staehr3,
- V. Chandramouli4,
- B.R. Landau4,
- P. Nowotny2,
- W. Waldhäusl2,
- E. Haslinger1 and
- M. Roden2
- 1Department of Pharmaceutical Chemistry, University of Graz, Graz, Austria
- 2Division of Endocrinology and Metabolism, Department of Internal Medicine III, University of Vienna, Vienna, Austria
- 3Department of Medical Endocrinology, Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
- 4Department of Medicine and Biochemistry, Case Western Reserve University, Cleveland, Ohio
- Address correspondence and reprint requests to Michael Roden, Division of Endocrinology and Metabolism, Department of Internal Medicine III, University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. E-mail: michael.roden{at}akh-wien.ac.at
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 μmol · 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 ∼100 to ∼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.
- EGP, endogenous glucose production
- FFA, free fatty acid
- HMT, hexamethylenetetramine
- MRS, magnetic resonance spectroscopy
- NMR, nuclear magnetic resonance
- PAG, d-pentaacetylglucose
- PEP, phosphoenolpyruvate
Footnotes
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O.K. and H.S. contributed equally to this work.
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- Accepted July 17, 2003.
- Received January 19, 2003.
