Measuring gluconeogenesis using a low dose of 2H2O: advantage of isotope fractionation during gas chromatography.
The contribution of gluconeogenesis to glucose production can be measured by enriching body water with (2)H(2)O to approximately 0.5% (2)H and determining the ratio of (2)H that is bound to carbon-5 vs. carbon-2 of blood glucose. This labeling ratio can be measured using gas chromatography-mass spectrometry after the corresponding glucose carbons are converted to formaldehyde and then to hexamethylenetetramine (HMT). We present a technique for integrating ion chromatograms that allows one to use only 0.05% (2)H in body water (i.e., 10 times less than the current dose). This technique takes advantage of the difference in gas chromatographic retention times of naturally labeled HMT and [(2)H]HMT. We discuss the advantage(s) of using a low dose of (2)H(2)O to quantify the contribution of gluconeogenesis.
Katanik
Jill
J
Department of Biochemistry, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, Ohio 44106, USA.
McCabe
Brendan J
BJ
Brunengraber
Daniel Z
DZ
Chandramouli
Visvanathan
V
Nishiyama
Fumie J
FJ
Anderson
Vernon E
VE
Previs
Stephen F
SF
D000818:Animals; D002247:Carbon Isotopes; D005591:Chemical Fractionation; D003903:Deuterium; D017666:Deuterium Oxide / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D008401:Gas Chromatography-Mass Spectrometry; D005943:Gluconeogenesis; D008297:Male; D008709:Methenamine; D051381:Rats; D017207:Rats, Sprague-Dawley
D002247:Carbon Isotopes; D003903:Deuterium; D008709:Methenamine; D017666:Deuterium Oxide