A 55-year-old man who has been suffering from chronic liver disease is diagnosed with elevated serum ammonia concentration. Failure of the liver to synthesize which of the following compounds most likely contributes to the increased serum ammonia concentration in this patient?

Question

Quizplus · Accepted Answer

The liver converts ammonia into urea through the urea cycle. In chronic liver disease, this process is impaired, leading to elevated ammonia levels. Glutamine is involved in ammonia detoxification, and its synthesis is affected in liver dysfunction.  Major hepatic reactions that involve the regulation of the level of circulating ammonia, include the enzymes glutamate dehydrogenase (GDH), glutamine synthase (GS), and glutaminase. The liver compartmentalizes GS and glutaminase in order to control the flow of ammonia into glutamine or urea. Under acidotic conditions, the liver diverts ammonia to glutamine via the GS reaction. The glutamine then enters the circulation. In fact, glutamine is the major amino acid of the circulation and its role is to ferry ammonia to and from various tissues.

A 55-Year-Old Man Who Has Been Suffering from Chronic Liver