Induction of fructose 1,6-bisphosphatase and glucose 6-phosphatase in fetal mouse liver

Abstract

Fructose 1,6-bisphosphatase and glucose 6-phosphatase were induced in organ cultures of liver tissues from 15- and 19-day-old fetal mice, using a culture method that allowed the tissues to be maintained for 7 days in the absence of serum. In cultures from 15-day-old fetal liver, both enzyme activities increased significantly per milligram of DNA after a lag period of 1 to 3 days. In cultures from 19-day-old fetal liver only glucose 6-phosphatase increased in the absence of inducer. N 6,O 2′ -Dibutyryladenosine 3′,5′-monophosphate enhanced the rate of increase in fructose 1,6-bisphosphatase and glucose 6-phosphatase activities. The minimum effective concentration of the cyclic nucleotide was approximately 10 −6 m. Dexamethazone inhibited the increase in fructose 1,6-bisphosphatase during culture for 7 days. Glucose 6-phosphatase activity was enhanced by dexamethazone in cultures from 19-day-old fetal liver, but was without effect on glucose 6-phosphatase in cultures from 15-day-old fetal liver. The minimum inhibitory concentration of dexamethazone was less than 10 −8 m. The results suggest a complicated effect of the cyclic nucleotide on the two enzymes in fetal mouse liver as well as different mechanisms of action of dexamethazone on the induction of two enzymes.