In vivo measurement of gluconeogenesis in animals and humans with deuterated water: a simplified method.
The contribution of gluconeogenesis to glucose production can be measured by comparing after ingestion of deuterated water the enrichment in deuterium of the hydrogen bound to carbon 5 of glucose with that of hydrogen bound to carbon 2 or with the deuterium enrichment of plasma water. The method developed by Landau et al. for measuring deuterium enrichment on carbon 5 by gas chromatography-mass spectrometry analysis is tedious and time consuming. We developed a simpler procedure for measuring this deuterium enrichment. Deuterium enrichment on carbons 5 and 6 of glucose is measured using the 1,2-5, 6-diisopropylidene-3-O-acetyl-a-furanosyl derivative. Enrichment in position 6 is measured using the hexamethylenetetramine procedure and subtracted from the enrichment on carbons 5 and 6 to obtain the specific enrichment on carbon 5. We tested first this method in post-absorptive and fasted rats (plasma water enrichment 0.6%) infused simultaneously with [6,6-(2) H(2) ] glucose in order to obtain not only the percent contribution of gluconeogenesis, but also glucose turnover rate and absolute gluconeogenesis flux. In post-absorptive and starved rats gluconeogenesis represented respectively 46.7+/-2.0% and 94.1+/-2.0% of glucose production and a flux of 31.1+/-1.8 and 38.9+/-0.9 micromol/kg/min. The method was then used in humans. The contribution in the post-absorptive state of gluconeogenesis to glucose appearance measured in control and type 2 diabetic subjects (plasma water enrichment 0.23-0.38%) was 40. 7+/-5.0% and 65.7 +/-3.3% (p<0.05) respectively. In conclusion this simplified method appears useful for in vivo studies of gluconeogenesis.
Saadatian
M
M
INSERM U. 499, Faculté RTH Laennec, rue Guillaume Paradin, 69372 Lyon Cedex 08, France.
Peroni
O
O
Diraison
F
F
Beylot
M
M
D000328:Adult; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D017666:Deuterium Oxide / Q000008:administration & dosage / Q000493:pharmacokinetics*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D004435:Eating; D005215:Fasting; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D005943:Gluconeogenesis; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D051381:Rats; D017207:Rats, Sprague-Dawley
D001786:Blood Glucose; D017666:Deuterium Oxide; D006442:Glycated Hemoglobin