PMID: 1680307Mar 1, 1991Paper

Control of urea synthesis and ammonia utilization in protein deprivation and refeeding

Archives of Biochemistry and Biophysics
V FelipoS Grisolía


Rats were fed a standard diet (20% protein) or a protein-free diet for up to 65 days. After 20 days on the protein-free diet some rats were refed the standard diet. By the 20th day the rats fed the protein-free diet showed a blood ammonia level approximately 70% higher than controls and urea excretion decreased approximately 20-fold. At this time the liver acetylglutamate decreased to approximately one-fifth of the initial and control levels, returning to normal after 3 days of refeeding the standard diet, with a concomitant increase in urea excretion. The protein-deficient diet resulted in decreased activities of liver enzymes related to ammonia metabolism. All enzyme activities assayed returned to normal values rapidly upon refeeding the standard diet, except hepatic carbamylphosphate synthetase, glutamine synthetase, and glutaminase, which took approximately 1 month to return to control values. The findings presented here are consistent with the view that urea production is controlled, at least under certain conditions, by acetylglutamate, the physiological activator of carbamylphosphate synthetase.


Mar 1, 1992·Hepatology : Official Journal of the American Association for the Study of Liver Diseases·E GrauS Grisolía
Aug 14, 1998·Artificial Organs·B AgroyannisK Chondros
Jun 1, 1999·Nutrition Research Reviews·J C Waterlow
Nov 5, 2014·Liver International : Official Journal of the International Association for the Study of the Liver·Olivia Vázquez-MartínezMauricio Díaz-Muñoz
Nov 13, 2014·European Journal of Clinical Nutrition·S BeckerC L Hvas
Mar 1, 1997·Annals of Clinical Biochemistry·B AgroyannisD Koutsikos

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