Abstract
An attempt was made to clarify the metabolic correlation in the urea concentration and arginase activity of rats during adaptation to low-protein diet. The following results were obtained.
The urea concentration in the serum and liver was significantly decreased for 14 days from the start of a 2% casein diet and then stayed constant. Similarly it was also observed that arginase activity in the liver of rats fed a 2% casein diet showed a lower value than that of a laboratory pellet chow group. On the contrary, the level of renal enzyme increased progressively by feeding the lowprotein diet. The results show that there is a clear difference between liver and kidney in the response of arginase activity to the dietary changes. In addition, the feeding of low-protein exhibited a marked decrease of the urea concentration excreted in the urine. However, these observations were not seen in the fasted rats, and also in the rats fed on essential amino acid-deficient diets.
