Marked hyperlipidaemia in rats bearing the Yoshida AH-130 ascites hepatoma.

Malignant tumour burden is a pathological s ta te associated with a considerable demand for nutrients by the growing tumour [l]. Although a great deal of work has been carried out, there are contradictory results about the effects of tumour burden on lipid metabolism both in experimental animals and man. Lipid oxidation has been reported either increased [2], unchanged [3] or decreased [4]. In addi t ion, lipoprotein lipase activity decreases in adipose tissue, with a concomitant increase in plasma triacylglycerol levels [5]. We have examined the effects on in vivo lipid metabolism induced by the presence of t h e rapidly growing tumour Yoshida AH-1 3 0 ascites hepatoma. Female Wistar rats fed ad libitum were injected intraperitoneally with a Yoshida AH-1 3 0 ascites hepatoma cell suspension (120 x 106 cells). T h e Yoshida AH-130 is a rapidly growing tumour with a volume doubling time of 1 day [6]. In these animals we examinated t h e metabolic fate of a n oral ly administered triolein [7], the lipoprotein lipase (LPL) activity [8], as well as the lipogenic rate [9]. We also determined the levels of both triacylglycerols (TAG) and non-esterified fatty acids (NEFA) in plasma. The experiments were performed either 4 or 7 days after tumour inoculation. The implantation of the Yoshida AH-130 ascites hepatoma resulted in a decrease in body weight. In addi t ion , t h e t u m o u r i n d u c e d a m a r k e d hyperlipidaemia, which was explained both by a n increased hepatic lipogenic rate and a decreased circulating triacylglycerol clearance: however, the animals showed a decrease in the i n t e s t i n a l absorption of a n oral triolein load. A1 t h o u g h hypophagia can explain some of the observed changes in lipid metabolism in this experimental model, others factors must be involved in fat depletion and hyperlipidaemia. Cytokines, tumour necrosis factor-a in particular, could explain some of the changes in lipid metabolism related with cancer cachexia [lo]. L-