Underestimation of D-glucose utilisation as judged from the conversion of D-[3-(3)H]glucose to (3)HOH.
OBJECTIVE
The conversion of D-[3-(3)H]glucose to (3) HOH is currently measured to assess D-glucose utilisation. The validity of such a procedure was re-evaluated.


METHODS
The conversion of D-[3-(3)H]glucose and D-[5-(3)H]glucose to (3) HOH was measured in rat pancreatic islets, parotid cells and erythrocytes. The tritiation of lipids were also examined in islets exposed to D-[3-(3)H]glucose or D-[5-(3)H]glucose.


RESULTS
In rat pancreatic islets and parotid cells, but not in rat erythrocytes, the generation of (3) HOH from D-[3-(3)H]glucose underestimates the rate of D-glucose utilisation, this being apparently attributable to a partial escape from detritiation of [1-(3)H]glycerone-3-phosphate. Such an escape phenomenon resulted in a higher tritiation of lipids in pancreatic islets exposed to D-[3-(3)H]glucose, rather than D-[5-(3)H]glucose. Its relative extent was affected by a number of environmental factors such as the cell type under consideration, the metabolic status of the animals, and the extracellular concentration of D-glucose.


CONCLUSIONS
These findings impose a reservation on the use of D-[3-(3)H]glucose conversion to (3)HOH as a tool to assess the utilisation of the hexose in some cell types.
Sener
A
A
Laboratory of Experimental Medicine, Brussels Free University, Brussels, Belgium.
Giroix
M-H
MH
Malaisse
W J
WJ
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D002250:Carbon Radioisotopes; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis; D007328:Insulin / Q000097:blood; D007515:Islets of Langerhans / Q000378:metabolism; D007553:Isotope Labeling / Q000379:methods*; D008297:Male; D051381:Rats; D012727:Sex Characteristics; D014316:Tritium; D014867:Water / Q000378:metabolism*
D000596:Amino Acids; D001786:Blood Glucose; D002250:Carbon Radioisotopes; D007328:Insulin; D014867:Water; D014316:Tritium; D005947:Glucose