AN INVERSE RELATIONSHIP BETWEEN LIVER ARGINASE ACTIVITY AND UREA EXCRETION IN RATS

Liver arginase activity in rats fed graded levels of diammonium citrate in high and low casein diets, was measured with simultaneous determination of urea excretion. The arginase activity changed inversely with the urea excretion. Moreover, when the amino acid balance was quantitatively changed by varying threonine level alone, a similar relationship between total liver arginase activity and urea excretion was again observed. From these results, the early teleological assumptions are most unlikely in that liver arginase activity increases with the decrease in dietary protein quality and that the change in activity can be used as an index of dietary protein quality. © 1969 Taylor and Francis Group LLC.