The amount of urea excretion was the highest in the high protein diet group. When each diet group was treated with alloxan, total urea excretion showed little differences between each diet group and its corresponding control group with the exception being in the normal diet group.

However, the enzyme activity of OTC was increased significantly by alloxan treatment in low and high protein diet groups as compared to corresponding control groups. Similar results were obtained in arginase activity, although the magnitude of the change was less marked.

In liver perfusion experiments on rats treated with alloxan, the amount of urea production and changes in OTC and arginase activity were very similar with those in the intact liver.

These results suggest that alloxan treatment in normal diet group causes an increase in urea excretion both in intact and perfused liver regardless of changes in enzyme activities and total urea excretion, and enzyme activities are affected by changes in dietary components but the changes of enzyme activities may not correlate with total urea excretion.