A Sener1, M-H Giroix, W J Malaisse. 1. Laboratory of Experimental Medicine, Brussels Free University, Brussels, Belgium.
Abstract
AIMS/HYPOTHESIS: 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. CONCLUSION/ INTERPRETATION: 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.
AIMS/HYPOTHESIS: 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 ratpancreatic 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 ratpancreatic 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. CONCLUSION/ INTERPRETATION: 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.