Liver regeneration factor detected in human serum after partial hepatectomy

We obtained blood sera from patients before and after partial hepatectomy, and estimated the activities of the sera in promoting DNA synthesis in a primary culture of rat hepatocytes. The stimulating activity in portal serum from patients without any postoperative complications increased significantly after liver resection; that in portal serum from patients with complications did not. The amount of stimulatory factor transported to the liver, calculated by use of the stimulating activity in portal serum and the portal blood flow, increased after partial hepatectomy. The maximum amount was correlated to the resection ratio (p less than 0.05) and seemed to be correlated to the increase in liver volume. These results suggest that a stimulatory factor or factors are present in portal serum after partial hepatectomy and that such a factor and portal blood flow are important in liver regeneration after surgery.