title: The regulation of glucose transporter gene expression by cyclic adenosine monophosphate in NIH3T3 fibroblasts.
abstract: The effect of cAMP on glucose transport was studied in fibroblastic cells. Incubation of confluent NIH3T3 cells for 6 h in the presence of cholera toxin (10 ng/ml) and 3-isobutyl-1-methylxanthine [(IBMX) 0.2 mM] or 8-bromo-cAMP (0.3 mM) and IBMX resulted in a 4-fold increase in the rate of deoxyglucose uptake; no change in hexose transport could be detected after treatment for 30 min. Either cholera toxin (0.3 ng/ml-30 ng/ml) or 8-bromo-cAMP (30 microM-3 mM) increased the expression of the mRNA encoding the glucose transporter (GT) protein, as determined by hybridization of size-fractionated total RNA to a rat brain GT cDNA. Activation of adenylate cyclase by forskolin also rapidly induced a 4- to 10-fold increase in GT mRNA. The rise in the level of GT mRNA was maximal 3-4 h after addition of the drug, and returned to basal values by 16 h. The stimulation was concentration dependent, with forskolin producing a maximal effect at 30 microM. The effect of a submaximal concentration (1 microM) of forskolin was greatly enhanced in the presence of IBMX (0.2 mM), which alone had little effect on GT mRNA levels. The forskolin-stimulated increase in GT mRNA was not blocked by inhibition of protein synthesis by cycloheximide (10 micrograms/ml) or anisomycin (100 microM). The involvement of GT gene transcription was assessed by the nuclear run-on assay. Treatment of the cells with 30 microM forskolin increased transcription 10-fold within 30 min; the activation was not blocked by cycloheximide.(ABSTRACT TRUNCATED AT 250 WORDS)
authors: Department of Cellular and Molecular Physiology, Harvard Medical School, Boston, Massachusetts 02115.
authors: Y
authors: Y
authors: Hiraki
authors: I M
authors: IM
authors: McMorrow
authors: M J
authors: MJ
authors: Birnbaum
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D000841:Anisomycin / Q000494:pharmacology; D001693:Biological Transport, Active; D002772:Cholera Toxin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology*; D005347:Fibroblasts; D005786:Gene Expression Regulation; D005947:Glucose / Q000378:metabolism; D066298:In Vitro Techniques; D009004:Monosaccharide Transport Proteins / Q000235:genetics*; D011493:Protein Kinase C / Q000502:physiology; D012313:RNA / Q000032:analysis; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D009004:Monosaccharide Transport Proteins; D005576:Colforsin; D012313:RNA; D000841:Anisomycin; D002772:Cholera Toxin; D000242:Cyclic AMP; D011493:Protein Kinase C; D005947:Glucose; D013755:Tetradecanoylphorbol Acetate; D015056:1-Methyl-3-isobutylxanthine