Decrease of calmodulin and actin in the plasma membrane of rat liver cells during proliferative activation.

After proliferative activation of rat liver cells in vivo by a partial hepatectomy a decrease of the calmodulin content in the three plasma membrane domains (blood sinusoidal, canalicular and lateral) was observed. At 24 hours after partial hepatectomy calmodulin was found to be 3 fold lower in the sinusoidal and lateral fractions whereas a 2 fold decrease was detected in the canalicular domain. Decreases on the actin levels have been also detected at 24 hours after a partial hepatectomy. Since at this time after surgery increases on nuclear actin and calmodulin have been reported, these results suggest the possibility that the actin and calmodulin dissociated from the plasma membrane after a partial hepatectomy could subsequently be translocated into the nuclei.