Amino acids and ammonia in liver disease

© 2004 by CRC Press LLC. The liver has a key function in nitrogen metabolism. Liver disease and the resulting hepatocellular failure adversely affect these processes and induce profound disturbances among others in nitrogen homeostasis. A crucial feature in this context is the diminished hepatic urea synthesis capacity, leading to an impaired capacity to detoxify ammonia. This diminished ammonia detoxification capacity combined with the usually existing intra- or extrahepatic shunting contributes to the development of systemic hyperammonemia,1,2 which may induce the much feared complication of hepatic encephalopathy.3,4 Hyperammonemia may be further aggravated by esophageal variceal bleeds in patients with cirrhosis and portal hypertension, leading to an even more pronounced disturbance of nitrogen homeostasis.