Plasma level of branched chain alpha-amino acids following its alpha-keto acid administration to rats.

Abstract

To detect the effective substance accelerating the conversion of branched chain alpha-keto acids (BCKA) to corresponding amino acids, some sugars, sugar alcohols, ethanol, octanoate and ATP were tested with intravenous injection of three BCKA to rats. Plasma leucine levels 30 min after BCKA injection in rats, which were infused with 2 M solution of fructose or sorbitol, reached the significantly high peak corresponding to 860% and 790% of the basal levels. Administration of ethanol (2 or 3.5 M) or octanoate (4.5 mM) also resulted in significantly high levels of leucine in plasma following BCKA injection as compared with control. Molar ratio of plasma branched chain amino acid (BCAA)/aromatic amino acid 30 min after BCKA injection increased to 12.9 in control rats. The ratios 60 and 120 min after BCKA administration were significantly higher in rats treated with ethanol (3.5 M) or octanoate (4.5 mM) than those in control. These results suggest that infusion of the metabolites inducing high NADH/NAD ratio in their metabolic pathways results in inhibition of BCKA decarboxylation and, as a result, enhancement of transamination of BCKA into BCAA.