Regulation of fructose 2,6-P 2 concentration in isolated hepatocytes

Abstract

The effect of hormones on fructose-2,6-P 2 level and fructose-6-P,2-kinase activity was examined using rat hepatocytes. The dose response curve shows the half-maximal effect of glucagon on fructose-2,6-P 2 occurs at 3 X 10 −13 M glucagon, whereas the half-maximal effect on cyclic AMP occurs at 3 × 10 −0 M. The decrease in fructose-2,6-P 2 parallels the decrease in fructose-6-P,2-kinase activity. Incubation of cells with dibutryl cyclic AMP and cyclic AMP results in a 2- to 3-fold decrease in fructose-2,6-P 2. Epinephrine (10 −5 M) mediates a 2-fold decrease in fructose-2,6-P 2; isoproterenol has no effect. These results suggest that regulation of fructose-6-P,2-kinase is complex, involving cyclic AMP-dependent and -independent mechanisms.