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.