Induction of glucose 6-phosphatase in cultured hepatoma cells by dexamethasone.
The synthetic glucocorticoid, dexamethasone, induced high levels of glucose 6-phosphatase in a line of cultured hepatoma cells (2S FAZA). This conflicts with current theory that glucocorticoids induce a microsomal translocase, specific for glucose 6-phosphate, but not the hydrolase itself. The earlier conclusion was based on experiments with rat livers in vivo in which cortisone was the inducing agent. In the present study, 5 X 10(-6) M dexamethasone induced a tenfold increase in glucose 6-phosphatase activity in "intact" as well as disrupted microsomes using either glucose 6-phosphate or mannose 6-phosphate as substrate. This induction was blocked by cycloheximide (50 micrograms/ml). The broad pH maxima between 5.5 and 7.0 were similar for both "intact" and disrupted microsomes.
D000818:Animals; D003513:Cycloheximide / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology*; D004790:Enzyme Induction; D005952:Glucose-6-Phosphatase / Q000096:biosynthesis*; D019298:Glucose-6-Phosphate; D005958:Glucosephosphates / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008114:Liver Neoplasms, Experimental / Q000201:enzymology*; D008360:Mannosephosphates / Q000378:metabolism; D008862:Microsomes, Liver / Q000201:enzymology
D005958:Glucosephosphates; D008360:Mannosephosphates; C027693:mannose-6-phosphate; D019298:Glucose-6-Phosphate; D003907:Dexamethasone; D003513:Cycloheximide; D005952:Glucose-6-Phosphatase