Glucagon stimulation of fructose 1,6-bisphosphatase phosphorylation in rat hepatocytes

Hepatocytes from fed rats were incubated with [32p]PO₄ in the absence and presence of glucagon. Fructose 1,6-bisphosphatase was isolated from extracts of the hepatocytes by the addition of antiserum specific for the enzyme, and the amount of ³²p incorporated into the enzyme was determined after sodium dodecyl sulfate/gel electrophoresis. Glucagon (10 nM) stimulated ³²p incorporation by 60 percent. Half-maximal stimulation of ³²p-incorporation was observed with 1.5 nM glucagon. The enzyme had an apparent M_r of 41,000 after sodium dodecyl sulfate/slab gel electrophoresis. The relationship of phosphorylation to activity of the enzyme is discussed.