title: Relationship between D-glucose oxidation and glycolysis in tumoral pancreatic islet cells with either rapid or decreased cell growth.
abstract: The relationship between glucose oxidation and glycolysis was examined in tumoral pancreatic islet cells with either rapid or decreased cell growth. In the control RINm5F cells, the utilization of D-[5-3H]glucose progressively augmented at increasing concentrations of D-glucose (0.2 to 16.7 mM), whereas D-[6-14C]glucose oxidation reached its maximal value at about 3.0 mM D-glucose. The 14CO2/3HOH ratio progressively decreased at increasing hexose concentrations, being about 5-times higher at 0.2 than 10.0-16.7 mM. These experiments were repeated in cells cultured in the presence of D,L-alpha-difluoromethylornithine, which inhibits RINm5F cell proliferation. At 0.2 mM D-glucose, 14CO2 output was severely decreased but 3HOH production little affected, resulting in a marked fall of the 14CO2/3HOH ratio. On the contrary, at 16.7 mM D-glucose, 3HOH formation was more markedly decreased than 14CO2 output, resulting in an increased 14CO2/3HOH ratio. These findings provide a model for the interference of cell growth with D-glucose metabolism in islet cells. Rapid growth causes a preferential stimulation of the Krebs cycle relative to glycolysis at a low glucose concentration, whilst increasing glycolysis more than oxidation at high concentrations of the hexose.
authors.affiliation: Fundacion Jimenez Diaz, Centro Asociado al Consejo Superior de Investigaciones Cientificas, Madrid, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Camara
authors.forename: C
authors.initials: C
authors.lastname: Galera
authors.forename: I
authors.initials: I
authors.lastname: Valverde
authors.forename: W J
authors.initials: WJ
authors.lastname: Malaisse
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000032:analysis; D002250:Carbon Radioisotopes; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002952:Citric Acid Cycle; D000518:Eflornithine / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis; D007340:Insulinoma / Q000378:metabolism*; D007700:Kinetics; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D011865:Radioisotope Dilution Technique; D051381:Rats; D014316:Tritium; D014407:Tumor Cells, Cultured
chemical_list: D002250:Carbon Radioisotopes; D014316:Tritium; D002245:Carbon Dioxide; D005947:Glucose; D000518:Eflornithine