Beneficial effects of branched-chain amino acids on altered protein and amino acid metabolism in liver cirrhosis: evaluation in a model of liver cirrhosis induced in rats with carbon tetrachloride

Abstract

The effect of branched-chain amino acids (BCAA) on the metabolism of protein, amino acids and ammonia was examined in rats with cirrhosis, with a special emphasis on the efficacy of early administration of BCAA. Liver cirrhosis was induced in rats by intraperitoneal injections of carbon tetrachloride (CCl 4). The rats were divided into three groups: early-, late- and untreated. The early- and late-treated groups were given BCAA rich food from the early and late stage of liver cirrhosis, while the untreated group was given standard food throughout. Concentrations of amino acids and ammonia in the plasma and the ornithine carbamyl transferase (OCT) activity in the liver were evaluated, and compared with control group after 15 weeks maintenance. Ammonia was significantly higher in the late- and untreated groups, but not in the early-treated group. BCAA, tyrosine, and methionine were significantly lower in the untreated and late-treated groups. Glutamine increased significantly in the un-, late- and early-treated groups. However, no significant differences were found among three groups. A significant difference was found in 3-methyl histidine (3-MH) between the early- and late-treated groups. This study suggests that the administration of BCAA from early stage of liver cirrhosis inhibits breakdown of protein and improves metabolism of protein, amino acids and ammonia.