Effect of valine-depleted total parenteral nutrition on fatty liver development in tumor-bearing rats.

Valine-depleted amino acid imbalance, while having a suppressive effect on tumor growth, may induce fatty liver. We administered valine-depleted total parenteral nutrition (TPN) solution to rats subcutaneously transplanted with ascites containing hepatoma AH-109A and examined the time course of the development of fatty liver. An accumulation of fatty vacuoles was observed in hepatocytes on day 4. To prevent the development of fatty liver in tumor-bearing rats, we administered a small amount of valine in addition to the valine-depleted imbalance solution via the central vein. Such treatment, however, resulted in neither the prevention of fatty liver development nor the suppression of tumor growth. To supply valine to the liver, we administered a low concentration of valine via the portal vein simultaneously with central venous administration of valine-depleted TPN solution. As a result, the peripheral blood valine level of these rats was < 0.5 that of the control group, but the valine in the liver was maintained at the same level as that of the control group, and accumulation of triacylglycerols in the liver was slight. However, the suppressive effect on tumor growth was maintained, as the tumor weight was suppressed to almost the same degree as that of rats administered only the valine-depleted solution.