STREAMLINE PHENOMENA IN LIVER METASTASIS OF GASTROINTESTINAL TUMOR - AN EXPERIMENTAL-STUDY USING RATS

The establishment of liver metastasis from gastrointestinal tumor is m ainly considered to be via the portal vein, but its precise mechanism is still unknown. The purpose of this study is to evaluate the signifi cance-of 'streamline' phenomena in liver metastasis of gastrointestina l tumor by means of an experimental model. An animal model for the met astatic liver tumor was made in the Donryu rat. Five million cells of AH-66 strain, alpha-fetoprotein (AFP) producing hepatoma cells maintai ned as an ascites type strain, were administered via portal vein. The superior mesenteric vein (group A), the inferior mesenteric vein (grou p B) and the splenic vein (group C) were used as the sites of injectio n. In every group, serum AFP levels were elevated after administration of AH-66 cells and no significant differences were revealed between e ach group. In the pathological specimens of the liver taken after 7 da ys, many tumorous lesions were seen microscopically with islet formati ons, but no definitive difference was seen in each lobe. The serum AFP concentration in group A was significantly higher than that in group C. The tissue AFP concentrations of the right lobe were significantly higher than those of the left in groups A and B, but significantly low er than those of the left lobe in group C. The results indicate that t he distribution and proliferation of tumor cells administered via port al vein differed depending upon the site of tumor injection in accorda nce with the 'streamline' phenomena.