Differences in lipid composition and proliferative activity of rat hepatoma-27 depending on the target organ

Proliferative activity and lipid composition (phospholipids and ganglioside s) were studied in rat hepatoma-27 transplanted subcutaneously or intrahepa tically (as models for primary and metastasizing tumors). The mitotic index of subcutaneously transplanted hepatoma far exceeded that of the intrahepa tically transplanted tumor. The overall amounts of both phospholipids and g angliosides increased appreciably in the subcutaneously growing hepatoma (i n contrast to the intrahepatically growing tumor) in comparison to the cont rol hepatic tissue. The ganglioside composition in the tumors differs from that in the liver: ganglioside GD3 appears, whereas gangliosides GD1b and G T1b decrease in amount in the intrahepatic tumor compared to the control li ver and disappear in the subcutaneously transplanted hepatoma. In both tumo r types, the amounts of both phosphatidylethanolamine and sphingomyelin exc eed the control values. Comparison of these results with previously reporte d data concerning the phospholipid and ganglioside composition in the regen erating rat liver indicates that the difference in the lipid composition be tween the subcutaneously and intrahepatically growing hepatomas-27 is due t o their different proliferative status and also their microenvironment.