Determination of glycerol turnover by stable-isotope technique in humans: a new [1,1,2,3,3-2H5]glycerol derivative for mass-spectrometry analysis.
The stable isotope-labeled [1,1,2,3,3-2H5]glycerol analyzed by negative-ion chemical ionization (NCI) mass spectrometry has been proven a valid tracer for studying glycerol kinetics in humans. Because of its high technical complexity, NCI mass spectrometry is available to only a few laboratories. Thus, the aim of our study was to create an alternative method for measuring [1,1,2,3,3-2H5]glycerol enrichment in plasma with a new derivative and positive-ion chemical ionization (PCI) mass spectrometry. It could be demonstrated that the trisacetyl[1,1,2,3,3-2H5]glycerol derivative was able to produce a fragment at m/z = 164 with sufficient intensity. Application of [1,1,2,3,3-2H5]glycerol in seven healthy volunteers resulted in reproducible measurements of basal glycerol turnover rates. The mean glycerol flux rate of 3.02 +/- 0.37 mumol.kg-1 body wt.min-1 after an overnight fast was similar to values reported from studies with comparable protocols. Physiological changes of lipolysis rates after 48 h of fasting followed by infusion of 4 mg.kg-1 body wt.min-1 glucose could also be adequately studied in one subject. Fast-induced elevated glycerol turnover at 7.56 mumol.kg-1 body wt.min-1, was substantially suppressed to 1.13 mumol.kg-1 body wt.min-1, when glucose was administered. The easily performed trisacetyl[1,1,2,3,3-2H5]glycerol derivative analyzed by PCI mass spectrometry is suitable for studying glycerol kinetics in humans.
Schricker
T
T
Clinic of Anesthesiology, Ulm University, Germany.
Albuszies
G
G
Kugler
B
B
Wachter
U
U
Georgieff
M
M
D000089:Acetic Anhydrides; D000328:Adult; D003903:Deuterium; D004951:Esterification; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005990:Glycerol / Q000097:blood*; D006801:Humans; D007700:Kinetics; D008066:Lipolysis; D008297:Male; D013058:Mass Spectrometry
D000089:Acetic Anhydrides; D005230:Fatty Acids, Nonesterified; C031800:acetic anhydride; D003903:Deuterium; D005990:Glycerol