title: GLUT-2 gene transfer into insulinoma cells confers both low and high affinity glucose-stimulated insulin release. Relationship to glucokinase activity.
abstract: The rat insulinoma cell line RIN 1046-38 loses glucose-stimulated insulin secretion as a function of time in culture. We found that the loss of glucose sensing in these cells was correlated with the loss of expression of GLUT-2 and glucokinase. Stable transfection of RIN cells with a plasmid containing the GLUT-2 cDNA conferred glucose-stimulated insulin release in intermediate but not high passage cells, with the near-maximal 3-fold increase occurring at 50 microM glucose. GLUT-2 expressing cells also exhibited a larger response to the combination of 5 mM glucose + 1 microM forskolin than untransfected cells (7.9 versus 1.6-2.7-fold, respectively). GLUT-2 expressing intermediate passage, but not high passage, RIN cells exhibited a 4-fold increase in glucokinase enzymatic activity relative to nonexpressing controls. Glucokinase activity was also increased by transfer of the GLUT-2 gene into intermediate passage RIN cells via recombinant adenovirus. Preincubation of GLUT-2 expressing intermediate passage RIN cells with 2-deoxyglucose to inhibit low Km hexokinases resulted in a glucose-stimulated insulin secretion response that was shifted toward the physiologic range. These studies indicate that GLUT-2 expression confers both a high and low affinity glucose-stimulated insulin secretion response to intermediate passage RIN cells.
authors.affiliation: Gifford Laboratories for Diabetes Research, University of Texas, Dallas 75235.
authors.forename: S
authors.initials: S
authors.lastname: Ferber
authors.forename: H
authors.initials: H
authors.lastname: BeltrandelRio
authors.forename: J H
authors.initials: JH
authors.lastname: Johnson
authors.forename: R J
authors.initials: RJ
authors.lastname: Noel
authors.forename: L E
authors.initials: LE
authors.lastname: Cassidy
authors.forename: S
authors.initials: S
authors.lastname: Clark
authors.forename: T C
authors.initials: TC
authors.lastname: Becker
authors.forename: S D
authors.initials: SD
authors.lastname: Hughes
authors.forename: C B
authors.initials: CB
authors.lastname: Newgard
mesh_terms: D019325:3-O-Methylglucose; D000256:Adenoviridae; D000818:Animals; D001692:Biological Transport; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D015870:Gene Expression; D005822:Genetic Vectors; D005941:Glucokinase / Q000096:biosynthesis / Q000378:metabolism; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D051273:Glucose Transporter Type 2; D006593:Hexokinase / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007340:Insulinoma / Q000378:metabolism*; D007700:Kinetics; D008757:Methylglucosides / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis / Q000378:metabolism*; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D051273:Glucose Transporter Type 2; D007328:Insulin; D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; D012333:RNA, Messenger; D019325:3-O-Methylglucose; D005576:Colforsin; D006593:Hexokinase; D005941:Glucokinase; D005947:Glucose