Plasma amino acid abnormalities in liver disease: comparative analysis of idiopathic portal hypertension, extrahepatic portal occlusion and liver cirrhosis.

To clarify the clinical significance of specific plasma amino acid abnormalities occurring in liver disorders with portal-systemic shunting, plasma amino acids and insulin levels were measured in idiopathic portal hypertension (IPH), extrahepatic portal occulusion (EHPO), and liver cirrhosis (LC). Three branched chain amino acids (BCAA: valine + leucine + isoleucine) were decreased in all three diseases in comparison with controls. Since plasma insulin measured during oral glucose tolerance tests did not specifically rise in LC, reduction of BCAA is not merely ascribed to hyperinsulinemia. Either portal-systemic shunting or some extent of liver damage may contribute to a fall in BCAA. Two aromatic amino acids (AAA: phenylalanine + tyrosine), which were within the normal range in EHPO and IPH, showed a marked increase in LC. Thus, changes of AAA probably mainly reflect the severity of the liver disease. The molar ratio of BCAA/AAA (MR) significantly correlated with ICG k, ICG R15, PT and the sum of blood ammonia in an oral ammonia tolerance test which may reflect the degree of hepatic disorder. MR diminished in the following decreasing order: controls, EHPO, IPH and LC.