D-glucose metabolism in normal dispersed islet cells and tumoral INS-1 cells.
The metabolism of D-glucose was characterized in both normal dispersed rat islet cells and the 2-mercaptoethanol-dependent insulin-secreting cells of the INS-1 line. The normal and tumoral islet cells differed from one another by the relative magnitude, concentration dependency and hierarchy of the increase in the production of 3HOH from D-[5-(3)H]glucose and 14C-labelled CO2, acidic metabolites and amino acids from D-[U-14C]glucose at increasing concentrations of the hexose. For instance, whilst the paired ratio between D-[U-14C]glucose oxidation and D-[5-(3)H]glucose utilization augmented in a typical sigmoidal manner in normal islet cells exposed to increasing concentrations of D-glucose, it progressively decreased under the same experimental conditions in INS-1 cells. Nevertheless, the absolute values and concentration-response relationship for the increase in ATP generation rate attributable to the catabolism of D-glucose were virtually identical in normal and tumoral cells. These findings indicate that the analogy in the secretory response to D-glucose of normal and INS-1 islet cells, although coinciding with a comparable response to the hexose in terms of ATP generation, contrasts with a vastly different pattern of D-glucose metabolism in these two cell types.
Nadi
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Laboratory of Experimental Medicine, Brussels Free University, Belgium.
Olivares
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E
Malaisse
W J
WJ
D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000818:Animals; D002250:Carbon Radioisotopes / Q000378:metabolism; D002469:Cell Separation; D002478:Cells, Cultured; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D014407:Tumor Cells, Cultured
D002250:Carbon Radioisotopes; D007328:Insulin; D000255:Adenosine Triphosphate; D005947:Glucose