Effect of a fast-growing ascites hepatoma (Yoshida AH-130) on proteinase activities in the rat liver.

The weight of the liver and its DNA content definitely increase in rats transplanted with the ascites hepatoma AH-130 (Yoshida). The specific activity of cathepsin B1 decreases progressively in the liver during the first week after transplantation reaching one third of the initial levels, whereas that of cathepsin D shows the opposite behaviour increasing to levels 40% higher than in controls. The activity of the two proteinases in the blood plasma varies in a similar way, though the modifications are even more pronounced than in the liver. The relevance of the changes in tissue proteinase activities to the liver growth in tumour-bearing animals is discussed.