Comparison of the Changes in Lipid Metabolism between Hepatoma-bearing and Lipopolysaccharide-treated Rats

To elucidate the mechanism for hyperlipidemia in the hepatoma-bearing state, changes in some parameters related to the lipid metabolism and serum tumor necrosis factor-α (TNF-α) level were examined in Donryu rats that had been subcutaneously implanted with an ascites hepatoma cell line of AH109A. These parameters were also examined in rats that had been given a single injection of lipopolysaccharide (LPS), a model for acute infection with TNF-α secretion into the blood circulation. The serum triglyceride and total cholesterol (Ch) levels were significantly higher in both the hepatoma-implanted and LPS-injected rats than in normal rats. The level of adipose tissue lipoprotein lipase was decreased by hepatoma implantation and LPS injection, while the hormone-sensitive lipase activity was increased by the same treatments. Fatty acid (FA) oxidation and Ch synthesis were also stimulated by both treatments. The serum TNF-α level was noticably elevated by hepatoma implantation and greatly by the LPS injection. This LPS injection increased hepatic FA synthesis. The serum high-density lipoprotein Ch level and hepatic Ch 7α-hydroxylase activity were not changed by the LPS injection. Hepatoma implantation led to hyperlipidemia and elevated the serum TNF-α level, as did the LPS injection.