Nuclear protein kinase activity in glucagon-stimulated perfused rat livers

Nuclei isolated from glucagon-stimulated perfused rat livers contained 2–3 times as much protein kinase activity as did nuclei from control animals. In the presence of either the heat-stable inhibitor or the protein kinase regulatory subunit the elevated cyclic AMP-independent enzyme activity from stimulated nuclei was inhibited to an activity equivalent to that found in controls.