Regulation of glucose-transporter gene expression by insulin in cultured human fibroblasts.
To clarify the effect of insulin on glucose-transporter (GT) biosynthesis, we determined GT mRNA levels in human cultured skin fibroblasts, using HepG2 GT cDNA as a probe. Insulin specifically increased the GT mRNA level in a time- and dose-dependent manner. Time-course study demonstrated that the mRNA level peaked within 3 h of insulin (1 x 10(-7) M) addition. After remaining elevated for several hours, mRNA decreased and returned to the basal level after 24 h. In the cell strains from seven normal subjects, the mean (+/- SE) GT mRNA level determined after 3 h of treatment with 1 x 10(-7) M insulin was 164.3 +/- 8.5% of the level found in untreated control cells. The insulin dose-response curve of GT mRNA levels showed that the maximum stimulation was elicited at 1 x 10(-7) M, and the half-maximum stimulation occurred at approximately 5 x 10(-10) M. Degradation rates of GT mRNA determined in the presence of actinomycin D were not different between insulin-treated and untreated cells. These results suggest that insulin increases GT gene expression in cultured human fibroblasts.
D002478:Cells, Cultured; D004247:DNA / Q000235:genetics; D003609:Dactinomycin / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D009004:Monosaccharide Transport Proteins / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000096:biosynthesis
D007328:Insulin; D009004:Monosaccharide Transport Proteins; D012333:RNA, Messenger; D003609:Dactinomycin; D004247:DNA