Metabolism of D-[1,2-13C]glucose and alpha-D-[1,2-13C]glucose pentaacetate in tumoral pancreatic islet cells.
Tumoral pancreatic islet cells of the RINm5F line were incubated, in groups of 25x106 cells each, for 120 min at 37 degrees C in media (5. 0 ml) containing either alpha-D-[1,2-13C]glucose pentaacetate (1.7 mM) or both D-[1,2-13C]glucose (1.7 mM) and acetate (8.5 mM). In both cases, the amounts of 13C-enriched metabolites (D-glucose, L-lactate and acetate) and non-enriched metabolites (acetate) recovered in the incubation medium after incubation were close to the initial amount of esterified or non-esterified D-[1, 2-13C]glucose and acetate, respectively. The 13C-enriched metabolites corresponded mainly to double-labelled D-[1, 2-13C]glucose, L-[2,3-13C]lactate and [1,2-13C]acetate. The output of L-[2,3-13C]lactate and [1,2-13C]acetate was about 3-4 times lower in the cells exposed to alpha-D-[1,2-13C]glucose pentaacetate than in those incubated with unesterified D-[1,2-13C]glucose. These findings indicate that, despite extensive hydrolysis of alpha-D-[1, 2-13C]glucose pentaacetate in the RINm5F cells, the hexose moiety of the ester is less efficiently metabolized than unesterified D-[1, 2-13C]glucose tested at the same molar concentration (1.7 mM) in the presence of 8.5 mM acetate. Thus, a higher utilization of the hexose moiety of alpha-D-glucose pentaacetate than that of unesterified D-glucose, as previously documented in isolated pancreatic islets, represents a far-from-universal situation.
Ladriere
L
L
Laboratory of Experimental Medicine, Brussels Free University, B-1070 Brussels, Belgium.
Kadiata
M M
MM
Verbruggen
I
I
Willem
R
R
Malaisse
W J
WJ
D000085:Acetates / Q000032:analysis; D007516:Adenoma, Islet Cell / Q000378:metabolism* / Q000473:pathology; D003470:Culture Media; D005947:Glucose / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D019344:Lactic Acid / Q000032:analysis; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D014407:Tumor Cells, Cultured
D000085:Acetates; D003470:Culture Media; C105128:glucose pentaacetate; D019344:Lactic Acid; D005947:Glucose