Casein kinase 2 activity increases in the prereplicative phase of liver regeneration

Cytosolic casein kinase activity increased up to 2-fold in the first 6 h after partial hepatectomy and then decreased to control values. This increase was due mainly to casein kinase 2, which reached maximal values at 6-8 h of liver regeneration. In contrast, casein kinase 1 showed a smaller increase at 4 h and then started to decrease reaching values of about 70% of control at 16 h. The increase in total casein kinase 2 was accompanied with an activation of the enzyme, as determined by the low/high beta-casein activity ratio assay. Administration of an acute dose of glucagon to control rats also increased the activity ratio but failed to cause any rise in total casein kinase 2 activity.