Regulation of amino acid metabolism by epinephrine

1990 ◽  
Vol 258 (5) ◽  
pp. E878-E887
Author(s):  
S. Del Prato ◽  
R. A. DeFronzo ◽  
P. Castellino ◽  
J. Wahren ◽  
A. Alvestrand
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Insulin Infusion ◽  
Acid Metabolism ◽  
Quadriceps Muscle ◽  
Branched Chain Amino Acids ◽  
Venous Catheterization ◽  
Branched Chain ◽  
Insulin Replacement

The effect of epinephrine on amino acid (AA) metabolism was examined in 33 healthy volunteers who participated in four studies. Nine subjects participated in study I, which consisted of four parts: euglycemic insulin clamp, insulin plus epinephrine, insulin plus epinephrine plus propranolol, and insulin plus propranolol. In study II six subjects received epinephrine with hepatic-femoral venous catheterization. In study III five individuals received epinephrine with somatostatin plus basal insulin replacement. In study IV quadriceps muscle biopsy was performed in six subjects after epinephrine or insulin infusion. Both epinephrine and insulin caused a generalized decline in all plasma AA except alanine. With combined epinephrine-insulin infusion, the decrease in plasma AA was additive. Propranolol blocked the hypoaminoacidemic effect of epinephrine but failed to alter the AA lowering action of insulin. Epinephrine, while maintaining basal insulinemia, reduced the catechol's hypoaminoacidemic effect by 39%. After epinephrine, splanchnic alanine uptake increased, but plasma alanine remained constant because of a parallel rise in muscle alanine production. Plasma/intracellular concentrations of branched-chain amino acids (BCAA) and all gluconeogenic amino acids, except alanine, decreased after both epinephrine and insulin. In summary, the effect of epinephrine on plasma/intracellular total, gluconeogenic, and BCAA concentrations is similar to insulin.

Amino acid metabolism in the Zucker diabetic fatty rat: effects of insulin resistance and of type 2 diabetes

2004 ◽  
Vol 82 (7) ◽  
pp. 506-514 ◽  
Author(s):  
Enoka P Wijekoon ◽  
Craig Skinner ◽  
Margaret E Brosnan ◽  
John T Brosnan
Keyword(s):  
Insulin Resistance ◽  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Plasma Concentrations ◽  
Branched Chain Amino Acids ◽  
Insulin Resistant ◽  
Branched Chain

We investigated amino acid metabolism in the Zucker diabetic fatty (ZDF Gmi fa/fa) rat during the prediabetic insulin-resistant stage and the frank type 2 diabetic stage. Amino acids were measured in plasma, liver, and skeletal muscle, and the ratios of plasma/liver and plasma/skeletal muscle were calculated. At the insulin-resistant stage, the plasma concentrations of the gluconeogenic amino acids aspartate, serine, glutamine, glycine, and histidine were decreased in the ZDF Gmi fa/fa rats, whereas taurine, α-aminoadipic acid, methionine, phenylalanine, tryptophan, and the 3 branched-chain amino acids were significantly increased. At the diabetic stage, a larger number of gluconeogenic amino acids had decreased plasma concentrations. The 3 branched-chain amino acids had elevated plasma concentrations. In the liver and the skeletal muscles, concentrations of many of the gluconeogenic amino acids were lower at both stages, whereas the levels of 1 or all of the branched-chain amino acids were elevated. These changes in amino acid concentrations are similar to changes seen in type 1 diabetes. It is evident that insulin resistance alone is capable of bringing about many of the changes in amino acid metabolism observed in type 2 diabetes.Key words: plasma amino acids, liver amino acids, muscle amino acids, gluconeogenesis.

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 The case for regulating indispensable amino acid metabolism: the branched-chain α-keto acid dehydrogenase kinase-knockout mouse

2006 ◽  
Vol 400 (1) ◽  
Author(s):  
Susan M. Hutson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Essential Amino Acids ◽  
The Body ◽  
Keto Acid ◽  
Acid Dehydrogenase ◽  
Indispensable Amino Acid ◽  
Branched Chain

BCAAs (branched-chain amino acids) are indispensable (essential) amino acids that are required for body protein synthesis. Indispensable amino acids cannot be synthesized by the body and must be acquired from the diet. The BCAA leucine provides hormone-like signals to tissues such as skeletal muscle, indicating overall nutrient sufficiency. BCAA metabolism provides an important transport system to move nitrogen throughout the body for the synthesis of dispensable (non-essential) amino acids, including the neurotransmitter glutamate in the central nervous system. BCAA metabolism is tightly regulated to maintain levels high enough to support these important functions, but at the same time excesses are prevented via stimulation of irreversible disposal pathways. It is well known from inborn errors of BCAA metabolism that dysregulation of the BCAA catabolic pathways that leads to excess BCAAs and their α-keto acid metabolites results in neural dysfunction. In this issue of Biochemical Journal, Joshi and colleagues have disrupted the murine BDK (branched-chain α-keto acid dehydrogenase kinase) gene. This enzyme serves as the brake on BCAA catabolism. The impaired growth and neurological abnormalities observed in this animal show conclusively the importance of tight regulation of indispensable amino acid metabolism.

scholarly journals Influence of Histidine Administration on Ammonia and Amino Acid Metabolism: A Review

2020 ◽  
pp. 555-564
Author(s):  
M Holeček
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Metabolism ◽  
Degradation Pathway ◽  
Branched Chain Amino Acids ◽  
Muscle Performance ◽  
Positive Effects ◽  
Tissue Protection ◽  
Extrahepatic Tissues ◽  
Branched Chain

Histidine (HIS) is an essential amino acid investigated for therapy of various diseases, used for tissue protection in transplantation and cardiac surgery, and as a supplement to increase muscle performance. The data presented in the review show that HIS administration may increase ammonia and affect the level of several amino acids. The most common are increased levels of alanine, glutamine, and glutamate and decreased levels of glycine and branched-chain amino acids (BCAA, valine, leucine, and isoleucine). The suggested pathogenic mechanisms include increased flux of HIS through HIS degradation pathway (increases in ammonia and glutamate), increased ammonia detoxification to glutamine and exchange of the BCAA with glutamine via L-transporter system in muscles (increase in glutamine and decrease in BCAA), and tetrahydrofolate depletion (decrease in glycine). Increased alanine concentration is explained by enhanced synthesis in extrahepatic tissues and impaired transamination in the liver. Increased ammonia and glutamine and decreased BCAA levels in HIS-treated subjects indicate that HIS supplementation is inappropriate in patients with liver injury. The studies investigating the possibilities to elevate carnosine (β-alanyl-L-histidine) content in muscles show positive effects of β-alanine and inconsistent effects of HIS supplementation. Several studies demonstrate HIS depletion due to enhanced availability of methionine, glutamine, or β-alanine.

scholarly journals Multi-omics data reveal genes that are relevant for muscular amino acids in the common carp

2020 ◽  
Author(s):  
Youxiu Zhu ◽  
Hanyuan Zhang ◽  
Peng Xu ◽  
Zixia Zhao ◽  
Jianxin Feng ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Common Carp ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Essential Amino Acids ◽  
Muscle Tissues ◽  
The Common ◽  
Branched Chain ◽  
Amino Acid Contents

Abstract Background Fish muscular amino acids are a series of essential nutrients that embrace essential amino acids, branched-chain amino acids and flavorous amino acids. Previous studies have found that amino acids have important physiological effects on fish growth and development, as they are involved in maintaining nitrogen balance and in the formation of enzymes and hormones. Amino acids, such as aspartic acid, glutamic acid, glycine and alanine, that can have a significant effect on fish umami taste are called flavorous amino acids. Nevertheless, the studies on the genetic mechanisms of amino acid metabolism in the common carp (Cyprinus carpio) are still limited. Results The purpose of this study was to examine the divergent patterns at the genomic, transcriptomic and epigenomic levels in fish with different amino acid contents. Genome-wide association analysis using 195 individuals of common carp was conducted, and 62 genes were identified to be associated with glycine, proline, and tyrosine content. RNA-Seq of samples with extreme contents of essential amino acids, branched-chain amino acids and flavorous amino acids was applied using brain, liver and muscle tissues, resulting in 1,643 differentially expressed genes. Whole-genome bisulfite sequencing identified 3,108 genes with differentially methylated promoters. Through the enrichment analysis of transcriptome and DNA methylation results, we screened out a series of enriched pathways associated with amino acid metabolism, including various categories of pathways spanning growth regulation, lipid metabolism, the citrate cycle and other signaling pathways. Integrated studies demonstrated prominent correlations between DGE and DMP for amino acid contents trait in brain and muscle tissues. Conclusion In summary, the multi-omics data revealed candidate genes and pathways correlated with amino acid metabolism. These results will promote the process of the genomic selection and breeding strategy in muscular amino acid contents of fish.

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