Simultaneous determination of glucose turnover, alanine turnover, and gluconeogenesis in human using a double stable-isotope-labeled tracer infusion and gas chromatography-mass spectrometry analysis
We have developed and validated a new method to measure simultaneously glucose turnover, alanine turnover, and gluconeogenesis in human, in steady and non-steady states, using a double stable-isotope-labeled tracer infusion and GC-MS analysis. The method is based on the concomitant infusion and dilution of D-(2,3,4,6,6-2H5)glucose and L-(1,2,3-13C3)alanine. The choice of the tracers was done on the basis of a minimal overlap between the ions of interest and those arising from natural isotopic abundances. Alanine was chosen as the gluconeogenic substrate because it is the major gluconeogenic amino acid extracted by the liver and, with lactate, constitutes the bulk of the gluconeogenic precursors. The method was validated by comparing the results obtained during simultaneous infusion of trace amounts of both stable isotope labeled compounds with the radioactive tracers (D-(3-3H)glucose and L-(1,2,3-14C3)alanine) in a normal and a diabetic subject; the radiolabeled tracers were used as the accepted reference procedure. A slight overestimation of glucose turnover (7.3 versus 6.8 in normal and 10.8 versus 9.2 mumol/kg min in diabetic subject) was noticed when the stable isotope-labeled tracers were used. For the basal turnover rate of alanine, similar values were obtained with both methods (6.2 mumol/kg min). For gluconeogenesis, higher values were observed in the basal state with the stable isotopes (0.42 versus 0.21 mumol/kg min); however, these differences disappeared in the postprandial period after the ingestion of a mixed meal. Despite those minor differences, the overall correlation with the reference method was excellent for glucose turnover (r = 0.87) and gluconeogenesis (r = 0.86).
- Research Organization:
- Clinical Research Institute of Montreal, Quebec
- OSTI ID:
- 5531730
- Journal Information:
- Anal. Biochem.; (United States), Vol. 2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALANINE-L
METABOLISM
GLUCOSE
BIOSYNTHESIS
CARBON 13
DEUTERIUM COMPOUNDS
DOUBLE LABELLING
ISOTOPE DILUTION
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ALANINE-ALPHA
ALANINES
ALDEHYDES
AMINO ACIDS
CARBOHYDRATES
CARBON ISOTOPES
CARBOXYLIC ACIDS
EVEN-ODD NUCLEI
HEXOSES
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LABELLING
LIGHT NUCLEI
MONOSACCHARIDES
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
SACCHARIDES
STABLE ISOTOPES
SYNTHESIS
550201* - Biochemistry- Tracer Techniques