Tumour and Host Tissue Responses to Branched-Chain Amino Acid Supplementation of Patients with Cancer

1994 ◽  
Vol 86 (3) ◽  
pp. 339-345 ◽  
Author(s):  
M. A. McNurlan ◽  
S. D. Heys ◽  
K. G. M. Park ◽  
J. Broom ◽  
D. S. Brown ◽  
...  
Keyword(s):  
Amino Acids ◽  
Body Weight ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Cancer Patients ◽  
Muscle Tissue ◽  
Branched Chain Amino Acids ◽  
Saline Control ◽  
Intravenous Nutrition ◽  
Branched Chain

1 Rates of protein synthesis have been measured from the incorporation of 57 mg of l-[1-13C]leucine/kg for 90 min into muscle tissue and colorectal tumours removed at surgery from cancer patients. 2. For the 20 h preceding surgery and during the measurement of protein synthesis, the patients received intravenous saline, conventional intravenous nutrition (0.2 g of N and 103 non-protein kJ/kg body weight) or intravenous nutrition enriched with the branched-chain amino acids leucine, isoleucine and valine (0.2 g of N with 30% from branched-chain amino acids and 103 non-protein kJ/kg body weight). 3. Conventional intravenous nutrition resulted in a significant stimulation of the rate of protein synthesis in both muscle tissue (2.64 ± 0.75%/day versus 1.78 ± 0.51%/day in saline control, means ± SD) and tumour tissue (43.9 ± 10.3%/day versus 22.6 ± 5.6%/day in saline control). 4. Pre-operative nutrition enriched with branched-chain amino acids was less effective than conventional intravenous nutrition in stimulating protein synthesis in both muscle and tumour. The rates of protein synthesis were 2.12 ± 0.41%/day in muscle and 33.7 ± 5.3%/day in the tumours. 5. The expression of proliferating cell nuclear antigen in sections of the tumours showed changes with intravenous feeding of the two different amino acid mixtures that were similar to the changes in protein synthesis, and these two variables were significantly correlated. This is evidence that feeding with conventional mixtures and mixtures enriched with branched-chain amino acids stimulates tumour growth. 6. In this study the mixture enriched with branched-chain amino acids provided no clear advantage for cancer patients, since a smaller response to branched-chain amino acids was observed in both tumours and host muscle tissue.

scholarly journals Amino acid infusion increases the sensitivity of muscle protein synthesis in vivo to insulin. Effect of branched-chain amino acids

1988 ◽  
Vol 254 (2) ◽  
pp. 579-584 ◽  
Author(s):  
P J Garlick ◽  
I Grant
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Branched Chain Amino Acids ◽  
Acid Infusion ◽  
Amino Acid Infusion ◽  
Branched Chain

Rates of muscle protein synthesis were measured in vivo in tissues of post-absorptive young rats that were given intravenous infusions of various combinations of insulin and amino acids. In the absence of amino acid infusion, there was a steady rise in muscle protein synthesis with plasma insulin concentration up to 158 mu units/ml, but when a complete amino acids mixtures was included maximal rates were obtained at 20 mu units/ml. The effect of the complete mixture could be reproduced by a mixture of essential amino acids or of branched-chain amino acids, but not by a non-essential mixture, alanine, methionine or glutamine. It is concluded that amino acids, particularly the branched-chain ones, increase the sensitivity of muscle protein synthesis to insulin.

Changes in leucine kinetics during meal absorption: effects of dietary leucine availability

1986 ◽  
Vol 250 (6) ◽  
pp. E695-E701 ◽  
Author(s):  
S. Nissen ◽  
M. W. Haymond
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Branched Chain Amino Acids ◽  
Whole Body ◽  
Constant Infusion ◽  
Leucine Oxidation ◽  
Amino Acid Availability ◽  
Dietary Amino Acid ◽  
Branched Chain

Whole-body leucine and alpha-ketoisocaproate (KIC) metabolism were estimated in mature dogs fed a complete meal, a meal devoid of branched-chain amino acids, and a meal devoid of all amino acids. Using a constant infusion of [4,5-3H]leucine and alpha-[1-14C]ketoisocaproate (KIC), combined with dietary [5,5,5-2H3]leucine, the rate of whole-body proteolysis, protein synthesis, leucine oxidation, and interconversion of leucine and KIC were estimated along with the rate of leucine absorption. Ingestion of the complete meal resulted in a decrease in the rate of endogenous proteolysis, a small increase in the estimated rate of leucine entering protein, and a twofold increase in the rate of leucine oxidation. Ingestion of either the meal devoid of branched-chain amino acids or devoid of all amino acids resulted in a decrease in estimates of whole-body rates of proteolysis and protein synthesis, decreased leucine oxidation, and a decrease in the interconversion of leucine and KIC. The decrease in whole-body proteolysis was closely associated with the rise in plasma insulin concentrations following meal ingestion. Together these data suggest that the transition from tissue catabolism to anabolism is the result, at least in part, of decreased whole-body proteolysis. This meal-related decrease in proteolysis is independent of the dietary amino acid composition or content. In contrast, the rate of protein synthesis was sustained only when the meal complete in all amino acids was provided, indicating an overriding control of protein synthesis by amino acid availability.

Role of Leucine in Protein Metabolism During Exercise and Recovery

2002 ◽  
Vol 27 (6) ◽  
pp. 646-662 ◽  
Author(s):  
Donald K. Layman
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Branched Chain Amino Acids ◽  
New Findings ◽  
Branched Chain

Exercise produces changes in protein and amino acid metabolism. These changes include degradation of the branched-chain amino acids, production of alanine and glutamine, and changes in protein turnover. One of the amino acid most affected by exercise is the branched-chain amino acid leucine. Recently, there has been an increased understanding of the role of leucine in metabolic regulations and remarkable new findings about the role of leucine in intracellular signaling. Leucine appears to exert a synergistic role with insulin as a regulatory factor in the insulin/phosphatidylinositol-3 kinase (PI3-K) signal cascade. Insulin serves to activate the signal pathway, while leucine is essential to enhance or amplify the signal for protein synthesis at the level of peptide initiation. Studies feeding amino acids or leucine soon after exercise suggest that post-exercise consumption of amino acids stimulates recovery of muscle protein synthesis via translation regulations. This review focuses on the unique roles of leucine in amino acid metabolism in skeletal muscle during and after exercise. Key words: branched-chain amino acids, insulin, protein synthesis, skeletal muscle

scholarly journals Changes in the concentration of specific amino acids in the serum of experimentally malnourished pigs

1970 ◽  
Vol 24 (2) ◽  
pp. 557-564 ◽  
Author(s):  
R. F. Grimble ◽  
R. G. Whitehead
Keyword(s):  
Amino Acids ◽  
Body Weight ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Protein Content ◽  
Branched Chain Amino Acids ◽  
Serum Amino Acids ◽  
Branched Chain ◽  
Free Serum ◽  
Metabolic Significance

1. The concentrations of individual free serum amino acids have been studied during the course of chronic protein malnutrition in experimentally malnourished pigs.2. Until growth was markedly impaired, reducing the protein content of the diet had no significant effect on serum amino acid composition.3. During the period when growth had practically ceased but kcal intake per kg body-weight was normal the concentrations of valine, leucine, isoleucine, threonine and eventually tyrosine fell, the levels of alanine and serine were above control levels and aspartic acid, glycine, methionine, phenylalanine, proline, arginine, histidine and lysine remained unaltered.4. When the kcal intake per kg fell below control levels, owing to anorexia, and the animals began to lose weight, the levels of alanine, glycine, serine and methionine fell and valine, leucine, isoleucine, threonine and tyrosine remained well below control levels.5. The physiological, nutritional and metabolic significance of these findings is considered. The changes in alanine and glycine concentration are discussed in terms of the regulation of gluconeogenesis. The reduction of the branched-chain amino acids is interpreted on the basis of their availability for synthetic and catabolic needs.

scholarly journals Influence of Glutamine and Branched-Chain Amino Acids Supplementation during Refeeding in Activity-Based Anorectic Mice

Nutrients ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3510
Author(s):  
Clément L’Huillier ◽  
Marine Jarbeau ◽  
Floriane Pingeon ◽  
Wafa Bahlouli ◽  
Emmeline Salameh ◽  
...  
Keyword(s):  
Amino Acids ◽  
Body Weight ◽  
Protein Synthesis ◽  
Fat Mass ◽  
Lean Mass ◽  
Branched Chain Amino Acids ◽  
Free Access ◽  
Partial Restoration ◽  
Branched Chain ◽  
Underlying Mechanisms

Background: Optimizing the refeeding of patients with anorexia nervosa remains important to limit somatic complications of malnutrition, as well as to avoid disease relapses by targeting persistent mood and intestinal disorders. We aimed to evaluate the effects of glutamine (Gln) and branched-chain amino acids (BCAA) supplementation during refeeding in activity-based anorectic (ABA) mice. Method: Male C57Bl/6 mice were randomized in control and ABA groups. Once ABA-induced malnutrition was established, mice were progressively refed or not. Refed mice had free access to drinking water supplemented or not with 1% Gln or 2.5% BCAA for 10 days. Results: A progressive refeeding was associated with a partial restoration of body weight and lean mass, while a fat mass rebound was observed. In addition, refeeding restored glucose and leptin. Gln did not affect these parameters, while BCAA tended to increase body weight, fat mass, and glycaemia. In the colon, refeeding improved total protein synthesis and restored the LC3II/LC3I ratio, a marker of autophagy. Gln supplementation enhanced colonic protein synthesis, which was associated with an increased p-p70S6kinase/p70S6kinase ratio, whereas these effects were blunted by BCCA supplementation. Conclusions: In ABA mice, Gln and BCAA supplementations during a progressive refeeding fail to restore body weight and lean mass. However, Gln supplementation improves total colonic protein synthesis conversely to BCAA. Further studies are needed to decipher the underlying mechanisms involved in these opposite results.

Effect of Cycloheximide on In Vitro and In Vivo Protein Synthesis by Certain Tissues of Rats and Pigeons with Special Reference to Muscle

1973 ◽  
Vol 51 (12) ◽  
pp. 933-941 ◽  
Author(s):  
Njanoor Narayanan ◽  
Jacob Eapen
Keyword(s):  
Amino Acids ◽  
Body Weight ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Amino Acid Incorporation ◽  
Contrast Administration ◽  
Acid Incorporation ◽  
Tissue Homogenates

The effect of cycloheximide in vitro and in vivo on the incorporation of labelled amino acids into protein by muscles, liver, kidneys, and brain of rats and pigeons was studied. In vitro incorporation of amino acids into protein by muscle microsomes, myofibrils, and myofibrillar ribosomes was not affected by cycloheximide. In contrast, administration of the antibiotic into intact animals at a concentration of 1 mg/kg body weight resulted in considerable inhibition of amino acid incorporation into protein by muscles, liver, kidneys, and brain. This inhibition was observed in all the subcellular fractions of these tissues during a period of 10–40 min after the administration of the precursor. Tissue homogenates derived from in vivo cycloheximide-treated animals did not show significant alteration in in vitro amino acid incorporation with the exception of brain, which showed a small but significant enhancement.

scholarly journals Effect of abomasal glucose infusion on alanine metabolism and urea production in sheep

2000 ◽  
Vol 84 (2) ◽  
pp. 157-163 ◽  
Author(s):  
T. Obitsu ◽  
D. Bremner ◽  
E. Milne ◽  
G. E. Lobley
Keyword(s):  
Amino Acids ◽  
Body Weight ◽  
Branched Chain Amino Acids ◽  
Flux Rate ◽  
Plasma Urea ◽  
Exogenous Glucose ◽  
Abomasal Infusion ◽  
Urea Production ◽  
Branched Chain ◽  
N Flux

The effect of abomasal infusion of glucose (120 kJ/d per kg body weight (BW)0·75, 758 mmol/d) on urea production, plasma alanine-N flux rate and the conversion of alanine-N to urea was studied in sheep offered a low-N diet at limited energy intake (500 kJ/d per kg BW0·75), based on hay and grass pellets. Glucose provision reduced urinary N (P= 0·040) and urea (P= 0·009) elimination but this was offset by poorer N digestibility. Urea-N production was significantly reduced (822v. 619 mmol/d,P= 0·024) by glucose while plasma alanine-N flux rate was elevated (295v. 342 mmol/d,P= 0·011). The quantity of urea-N derived from alanine tended to be decreased by glucose (127v. 95 mmol/d) but the fraction of urea production from alanine was unaltered (15 %). Plasma urea and alanine concentrations (plus those of the branched chain amino acids) decreased in response to exogenous glucose, an effect probably related to enhanced anabolic usage of amino acids and lowered urea production.

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