Ammonia-induced changes in pancreatic hormones and plasma amino acids in patients with liver cirrhosis.

The contribution of hyperammonemia to plasma amino acid imbalance in patients with liver disease was assessed in 10 subjects with chronic hepatitis and in 17 advanced cirrhotics. Insulin, glucagon, and plasma amino acids were determined both in the basal state and 45 min after oral ammonium chloride, at doses used in the ammonia-tolerance test. In cirrhotics, ammonia increased to 3 times basal values, in association with a rise in insulin and, more marked, in glucagon. Aromatic amino acids and free tryptophan further increased, while a significant fall in branched-chain amino acids and glutamate was observed. The increase in ammonia levels strongly correlated with the increase in glucagon (r = 0.707). Two patients, with large esophageal varices, showed signs of disturbed consciousness, in association with a marked rise in ammonia and in the ration of free tryptophan to the sum of neutral amino acids. In patients with chronic hepatitis, whose ammonia levels rose slightly, minor variations in pancreatic glucoregulatory hormones and plasma amino acids were observed, as also happened in 10 healthy subjects following ammonium chloride ingestion. Our data fit with the hypothesis that the plasma amino acid imbalance of cirrhotics may be partly due to ammonia-induced changes in pancreatic hormones.