Role of N-Aeetylglutamate Turnover in Urea Synthesis of Rats Given Proteins of Different Quality

Abstract

The purpose of this study was to find whether the synthesis and degradation of N-acetylglutamate would affect urea synthesis when the dietary protein quality was manip-ulated. Experiments were done on three groups of rats given diets containing 10g gluten, 10g casein or 10g whole egg protein/100g for 10d. The urinary excretion of urea, the liver concentrations of N-acetylglutamate and free glutamate, the liver activity of N-acetyl-glutamate synthetase increased with the decline in quality of dietary protein. A reverse cor-relation was observed between the liver N-acetylglutamate degradation and liver N-acetylglutamate concentration. N-Acetylglutamate concentration in the liver was closely correlated with the concentration of glutamate and the N-acetylglutamate synthetase activity in the liver, and excretion of urea. These results suggest that the greater synthesis and the lower degradation rate of N-acetylglutamate in the liver of rats given the lower quality of protein increase the liver concentration of N-acetylglutamate and stimulate urea synthesis.