Effect of insulin on the induction by dexamethasone of glucose-6-phosphohydrolase and translocase activities in cultured hepatoma cells.
The ten-fold increase in glucose-6-phosphatase, previously reported, in 2S FAZA hepatoma cells exposed to dexamethasone, is completely blocked by low concentrations of insulin. At 3 x 10(-10) M insulin, the activity induced by 10(-6) M dexamethasone is reduced by half. The activity of intact microsomes, which reflects translocation of cytoplasmic glucose 6-phosphate into the endoplasmic reticulum, is induced by dexamethasone, but to a lesser extent than the hydrolase. Insulin also prevents this induction.
Garland
R C
RC
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115.
D000818:Animals; D017920:Antiporters; D002460:Cell Line; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology*; D004790:Enzyme Induction; D005952:Glucose-6-Phosphatase / Q000096:biosynthesis*; D007328:Insulin / Q000494:pharmacology*; D008114:Liver Neoplasms, Experimental / Q000201:enzymology*; D008862:Microsomes, Liver / Q000201:enzymology; D009004:Monosaccharide Transport Proteins; D010770:Phosphotransferases / Q000096:biosynthesis*
D017920:Antiporters; D007328:Insulin; D009004:Monosaccharide Transport Proteins; C111261:glucose 6-phosphate(transporter); D003907:Dexamethasone; D010770:Phosphotransferases; D005952:Glucose-6-Phosphatase