Method for the determination of the arteriovenous muscle protein balance during non-steady-state blood and muscle amino acid concentrations

2005 ◽  
Vol 289 (6) ◽  
pp. E1064-E1070 ◽  
Author(s):  
Christos S. Katsanos ◽  
David L. Chinkes ◽  
Melinda Sheffield-Moore ◽  
Asle Aarsland ◽  
Hisamine Kobayashi ◽  
...  
Keyword(s):  
Steady State ◽  
Amino Acid ◽  
Muscle Protein ◽  
Volume Of Distribution ◽  
Protein Balance ◽  
Nonsteady State ◽  
Balance Technique ◽  
Amino Acid Concentrations ◽  
Rate Of Accumulation

We describe a method based on the traditional arteriovenous balance technique in conjunction with muscle biopsies for the determination of leg muscle protein balance during the nonsteady state in blood amino acid concentrations. Six young, healthy individuals were studied in the postabsorptive state (pre-Phe) and after a bolus ingestion of ∼0.5 g phenylalanine (post-Phe). Post-Phe free phenylalanine concentrations in blood and muscle increased ( P < 0.05), but the respective concentrations of the amino acid threonine did not change. The average post-Phe leg net balance (NB) for threonine decreased from basal ( P < 0.05), but that for phenylalanine did not change. A volume of distribution for free phenylalanine in the leg was calculated based on the leg lean mass and the relative muscle water content and used to estimate the rate of accumulation of free phenylalanine in the leg. When the post-Phe NB for phenylalanine was corrected for the rate of accumulation of free phenylalanine in the leg, the post-Phe NB for phenylalanine decreased from basal ( P < 0.05). This corrected value was not different ( P > 0.05) from the value predicted for the phenylalanine NB based on the pre- and post-Phe NB responses for threonine. We conclude that the protein NB in non-steady-state blood phenylalanine concentrations can be determined from the arteriovenous phenylalanine NB by accounting for changes in free phenylalanine within its volume of distribution.

scholarly journals Determination of total amino acid concentrations in plasma

1970 ◽  
Vol 29 (1) ◽  
pp. 104-105 ◽  
Author(s):  
J. S. Slater ◽  
E. Joan Dunnett
Keyword(s):  
Amino Acid ◽  
Total Amino Acid ◽  
Amino Acid Concentrations

Noncompartmental Determination of the Steady‐State Volume of Distribution

1979 ◽  
Vol 68 (8) ◽  
pp. 1071-1074 ◽  
Author(s):  
Leslie Z. Benet ◽  
Renato L. Galeazzi
Keyword(s):  
Steady State ◽  
Volume Of Distribution

Free Amino Acid Pool and Muscle Protein Balance after Resistance Exercise

2003 ◽  
Vol 35 (5) ◽  
pp. 784-792 ◽  
Author(s):  
HANNU T. PITK??NEN ◽  
TARJA NYK??NEN ◽  
JUHA KNUUTINEN ◽  
KAISA LAHTI ◽  
OLAVI KEIN??NEN ◽  
...  
Keyword(s):  
Amino Acid ◽  
Resistance Exercise ◽  
Free Amino Acid ◽  
Free Amino ◽  
Muscle Protein ◽  
Amino Acid Pool ◽  
Protein Balance ◽  
Free Amino Acid Pool ◽  
Acid Pool

scholarly journals Effects of Salmon Ingestion on Post-Exercise Muscle Protein Synthesis: Exploration of Whole Protein Foods Versus Isolated Nutrients

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 650-650
Author(s):  
Kevin Paulussen ◽  
Amadeo Salvador ◽  
Colleen McKenna ◽  
Susannah Scaroni ◽  
Alexander Ulanov ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Myofibrillar Protein ◽  
Post Exercise ◽  
Exercise Muscle ◽  
Amino Acid Concentrations ◽  
Myofibrillar Protein Synthesis ◽  
Stimulation Of

Abstract Objectives Healthy eating patterns consist of eating whole foods as opposed to single nutrients. The maintenance of skeletal muscle mass is of particular interest to overall health. As such, there is a need to underpin the role of eating nutrients within their natural whole-food matrix versus isolated nutrients on the regulation of postprandial muscle protein synthesis rates. This study assessed the effects of eating salmon, a potential food within a healthy Mediterranean style eating pattern, on the stimulation of post-exercise muscle protein synthesis rates versus eating these same nutrients in isolation in healthy young adults. Methods In a crossover design, 10 recreationally active adults (24 ± 4 y; 5 M, 5 F) performed an acute bout of resistance exercise followed by the ingestion of salmon (SAL) (20.5 g protein and 7.5 g fat) or its matched constituents in the form of crystalline amino acids and fish oil (ISO). Blood and muscle biopsies were collected at rest and after exercise at 2 and 5 h during primed continuous infusions of L-[ring-2H5]phenylalanine for the measurement of myofibrillar protein synthesis and plasma amino acid profiles. Data were analyzed by using a 2-factor (time × condition) repeated-measures ANOVA with Tukey's post hoc test. Results Plasma essential amino acid concentrations increased to a similar extent in both SAL and ISO during the postprandial period (P &gt; 0.05). Likewise, postprandial plasma leucine concentrations did not differ between nutrient condition (P &gt; 0.05). The post-exercise myofibrillar protein synthetic responses were similarly stimulated in both nutrition conditions early (0–2 h; 0.079 ± 0.039%/h (SAL) compared to 0.071 ± 0.078%/h (ISO); P = 0.64) and returned to baseline later (2–5 h; 0.046 ± 0.020%/h (SAL) compared to 0.038 ± 0.025%/h (ISO); P = 0.90). Similarly, there were no differences in the stimulation of myofibrillar protein synthesis rates between SAL and ISO during the entire 0–5 h recovery period (0.058 ± 0.024%/h compared to 0.045 ± 0.027%/h, respectively; P = 0.66). Conclusions We show that the ingestion of salmon or its isolated nutrients increases plasma amino acid concentrations and enhances the stimulation of post-exercise muscle protein synthesis rates with no differences in the temporal or cumulative responses in healthy young adults. Funding Sources USDA National Institute of Food and Agriculture Hatch project.

scholarly journals Reduced amino acid availability inhibits muscle protein synthesis and decreases activity of initiation factor eIF2B

2003 ◽  
Vol 284 (3) ◽  
pp. E488-E498 ◽  
Author(s):  
Hisamine Kobayashi ◽  
Elisabet Børsheim ◽  
Tracy G. Anthony ◽  
Daniel L. Traber ◽  
John Badalamenti ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Amino Acid Replacement ◽  
Plasma Amino Acid ◽  
Initiation Factor ◽  
Nucleotide Exchange ◽  
Amino Acid Availability ◽  
Amino Acid Concentrations

We have examined the effect of a hemodialysis-induced 40% reduction in plasma amino acid concentrations on rates of muscle protein synthesis and breakdown in normal swine. Muscle protein kinetics were measured by tracer methodology using [2H5]phenylalanine and [1-13C]leucine and analysis of femoral arterial and venous samples and tissue biopsies. Net amino acid release by muscle was accelerated during dialysis. Phenylalanine utilization for muscle protein synthesis was reduced from the basal value of 45 ± 8 to 25 ± 6 nmol · min−1 · 100 ml leg−1 between 30 and 60 min after start of dialysis and was stimulated when amino acids were replaced while dialysis continued. Muscle protein breakdown was unchanged. The signal for changes in synthesis appeared to be changes in plasma amino acid concentrations, as intramuscular concentrations remained constant throughout. The changes in muscle protein synthesis were accompanied by a reduction or stimulation, respectively, in the guanine nucleotide exchange activity of eukaryotic initiation factor (eIF)2B following hypoaminoacidemia vs. amino acid replacement. We conclude that a reduction in plasma amino acid concentrations below the normal basal value signals an inhibition of muscle protein synthesis and that corresponding changes in eIF2B activity suggest a possible role in mediating the response.

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