Glucose transport by radiation-induced insulinoma and clonal pancreatic beta-cells.
Sugar uptake was measured in dispersed cells prepared from radiation-induced insulinomas transplantable in NEDH rats and in three clonal beta-cell lines maintained in continuous culture (RIN m5F, RIN 1046, HIT). Uptake of D-glucose and 3-O-methyl-D-glucose by insulinoma cells was rapid so that the intracellular concentration of D-hexoses approximated the concentration in the incubation medium by 15-30 s. L-Glucose was taken up only slowly. 3-O-methyl-D-glucose uptake by RIN m5F, RIN 1046, and HIT cells was slow; with 1 mM 3-O-methylglucose in the medium, equilibrium was attained at 20 min, but with 10 mM 3-O-methylglucose, equilibrium was not attained even at 20 min. In HIT cells incubated with D-glucose for 30 min, the intracellular concentration of glucose was less than the medium glucose concentration, indicating glucose transport is a nonequilibrium reaction in this cell line. These data indicate that radiation-induced insulinoma cells retain the capacity of normal beta-cells to transport sugar at high rates. RIN m5F, RIN 1046, and HIT cells transport sugar slowly, however, and thus differ from normal beta-cells. In RIN m5F, RIN 1046, and HIT cells, unlike in normal beta-cells, glucose transport may be the site regulating glucose metabolism.
D019325:3-O-Methylglucose; D007516:Adenoma, Islet Cell / Q000378:metabolism*; D000818:Animals; D001693:Biological Transport, Active; D002999:Clone Cells; D005947:Glucose / Q000378:metabolism*; D007340:Insulinoma / Q000378:metabolism*; D007515:Islets of Langerhans / Q000378:metabolism*; D008757:Methylglucosides / Q000378:metabolism; D009368:Neoplasm Transplantation; D009381:Neoplasms, Radiation-Induced / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D051381:Rats
D008757:Methylglucosides; D019325:3-O-Methylglucose; D005947:Glucose