Amounts Of Branched-chain Amino Acids Research Articles

Effects of ammonium chloride administration on ammonia and free amino acid levels in erythrocytes and plasma of carp.

Changes in ammonia (NH3+NH4+) and free amino acid levels in the erythrocytes and plasmaof carp Cyprinus carpio were examined after intraperitoneal injection of ammonium chloride dissolved in Ringer's solution at a rate of 400μmol per 100g body weight. Ammonia levels bothin the erythrocytes and plasma reached the maximum levels at 3 min after the treatment and droppe to the initial levels by 120 min. The pealdevels in the erythrocytes and plasma were 5.7 times and 13.2 times higher than the respective initial values. Percentages of ammonia contentin the erythrocytes were always more than 37% of the whole blood, which indicates that not only plasma but also erythrocytes play a certain role in the inter-organ transport of ammonia. Although most of the free amino acids including glutamic acid and glutamine did not show any consistent changes, the total amounts of branched-chain amino acids both in the erythrocytes and plasma changed slightly but significantly in a reverse manner to the ammonia levels.

Branched-Chain Amino Acids in Sepsis and Hepatic Failure

The pathophysiologic mechanisms for the metabolism of hepatic failure and severe sepsis are complex, and in many ways similar. The similarities concern abnormalities in peripheral and hepatic protein metabolism. The ability of enteral and parenteral solutions containing increased amounts of branched-chain amino acids to ameliorate many of the derangements observed in these disease states relates to this shared pathophysiology.

The optimal branched-chain to total amino acid ratio in the injury-adapted amino acid formulation.

Several recent studies have suggested that solutions containing increased amounts of branched-chain amino acids (BCAA) might be useful in the treatment of patients with trauma and/or sepsis. In this study we investigated the optimal amount of BCAA in a balanced nutritional solution in an injured rat laparotomy model. The amino acid content of a standard BCAA-enriched amino acid solution was enriched to 40, 45, and 50% by the addition of equimolar amounts of the three BCAA. Rats were infused with either 3.6 cal/100 g body weight/24 hr or with 18 cal/100 g body weight/24 hr with either a 40, 45, or 50% BCAA mixture and evaluated for nitrogen balance, plasma amino acid levels, and levels of plasma blood urea nitrogen, creatinine, glucose, albumin, and blood ammonia. Nitrogen balance was negative in rats receiving only 3.6 cal/100 g body weight/24 hr, but was least negative in the group receiving 45% BCAA. Nitrogen balance was positive in groups receiving 18 cal/100 g body weight/24 hr, but was most positive in groups receiving 40 or 45% BCAA-containing solutions. Plasma amino acid patterns were least distorted in the 40 and 45% formulations. Blood ammonia was highest in the 40% BCAA group and plasma albumin was best maintained in the 45% BCAA group regardless of the amount of caloric supply. The results suggest that a 45% BCAA-enriched solution is the most appropriate in this injured rat model.

Effects of Branched-chain Amino Acid Antagonism in the Rat on Tissue Amino Acid and Keto Acid Concentrations

Growth rate, plasma amino acid, and alpha-keto acid concentrations and activities of the branched-chain amino acid degradative enzymes of rats were measured. Effects of ingestion of excessive amounts of branched-chain amino acids on these variables were determined. Excessive intake of a single branched-chain amino acid led rapidly to elevated plasma concentration of both the amino acid administered and its corresponding alpha-keto acid and, if the rats had previously been fed a low protein diet, to an increase in liver branched-chain alpha-keto acid dehydrogenase activity. Only leucine caused, in addition, marked growth and food intake depression and decreased plasma isoleucine, valine, alpha-keto-beta-methylvaleric acid and alpha-keto isovaleric acid concentrations. The growth depression was associated food intake depression and could be moderated by addition of isoleucine and valine to the diet. The decreases in plasma isoleucine, valine, alpha-keto-beta-methylvaleric acid and alpha-keto isovaleric acid were not caused by increased degradation of these metabolites to carbon dioxide as branched-chain amino acid oxidation rates in vivo were unchanged by leucine loading and the degradative enzymes were unchanged in adequately fed rats. The decreased concentrations of these amino and keto acids may be the result of decreased protein degradation or increased protein synthesis, possibly mediated by insulin.