Branched-chain amino acid supplementation during bed rest: effect on recovery

2003 ◽  
Vol 94 (4) ◽  
pp. 1345-1352 ◽  
Author(s):  
T. P. Stein ◽  
M. R. Donaldson ◽  
M. J. Leskiw ◽  
M. D. Schluter ◽  
D. W. Baggett ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Glucose Production ◽  
Bed Rest ◽  
Recovery Phase ◽  
Whole Body ◽  
N Retention ◽  
Gluconeogenesis From Alanine ◽  
Total Glucose

Bed rest is associated with a loss of protein from the weight-bearing muscle. The objectives of this study are to determine whether increasing dietary branched-chain amino acids (BCAAs) during bed rest improves the anabolic response after bed rest. The study consisted of a 1-day ambulatory period, 14 days of bed rest, and a 4-day recovery period. During bed rest, dietary intake was supplemented with either 30 mmol/day each of glycine, serine, and alanine ( group 1) or with 30 mmol/day each of the three BCAAs ( group 2). Whole body protein synthesis was determined with U-15N-labeled amino acids, muscle, and selected plasma protein synthesis withl-[2H5]phenylalanine. Total glucose production and gluconeogenesis from alanine were determined with l-[U-13C3]alanine and [6,6-2H2]glucose. During bed rest, nitrogen (N) retention was greater with BCAA feeding (56 ± 6 vs. 26 ± 12 mg N · kg−1 · day−1, P < 0.05). There was no effect of BCAA supplementation on either whole body, muscle, or plasma protein synthesis or the rate of 3-MeH excretion. Muscle tissue free amino acid concentrations were increased during bed rest with BCAA (0.214 ± 0.066 vs. 0.088 ± 0.12 nmol/mg protein, P < 0.05). Total glucose production and gluconeogenesis from alanine were unchanged with bed rest but were significantly reduced ( P < 0.05) with the BCAA group in the recovery phase. In conclusion, the improved N retention during bed rest is due, at least in part, to accretion of amino acids in the tissue free amino acid pools. The amount accreted is not enough to impact protein kinetics in the recovery phase but does improve N retention by providing additional essential amino acids in the early recovery phase.

Meal stimulation of albumin synthesis: a significant contributor to whole body protein synthesis in humans

1992 ◽  
Vol 263 (4) ◽  
pp. E794-E799 ◽  
Author(s):  
P. De Feo ◽  
F. F. Horber ◽  
M. W. Haymond
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Combined Treatment ◽  
Essential Amino Acids ◽  
Whole Body ◽  
Albumin Synthesis ◽  
Body Protein ◽  
Peripheral Tissues ◽  
Stimulation Of

The present studies were performed to test the hypothesis that the liver, by increasing the synthesis of specific plasma proteins during the absorption of an amino acid meal, may play an important role in the temporary "storage" of ingested essential amino acids and to explore the effects of glucocorticosteroids and recombinant human growth hormone (rhGH) on these processes. The fractional synthetic rates of albumin and fibrinogen were determined using simultaneous infusions of intravenous [1-14C]leucine and intraduodenal [4,5-3H]leucine after 22 h fasting and during absorption of glucose and amino acids in four groups of normal subjects treated for 1 wk with placebo, prednisone (0.8 mg.kg-1.day-1), rhGH (0.1 mg.kg-1.day-1), or combined treatment. When compared with the fasted state and independent of the route of tracer delivery and hormonal treatment, albumin, but not fibrinogen, synthesis increased (P < 0.0001) during absorption of a mixed glucose amino acid meal in all groups. This increase in albumin synthesis accounted for 28% of the increase in whole body protein synthesis associated with feeding and for 24, 22, and 14% in the prednisone, rhGH, and combined treatment groups, respectively. These data suggest that the stimulation of albumin synthesis observed during feeding prevents irreversible oxidative losses of a significant fraction of ingested essential amino acids and may serve as a vehicle to capture excess dietary amino acids and transport them to peripheral tissues to sustain local protein synthesis.

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.

Sulfur amino acid metabolism in the whole body and mammary gland of the lactating Saanen goat

1999 ◽  
Vol 50 (3) ◽  
pp. 413 ◽  
Author(s):  
J. Lee ◽  
R. J. Knutson ◽  
S. R. Davis ◽  
K. Louie ◽  
D. D. S. Mackenzie ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Mammary Gland ◽  
Amino Acid ◽  
Significant Proportion ◽  
Oxidation Products ◽  
Whole Body ◽  
Acid Uptake ◽  
Saanen Goat ◽  
Arterial Blood

Five multiparous Saanen goats in late lactation were infused with 35S-cysteine into the mammary gland via the external pudic artery. A further 2 goats were infused with 35S-methionine via the same artery and later with 35S-methionine into the jugular vein. Total uptake of cysteine from the arterial blood supply by the mammary gland was approximately 6% of the 35S-cysteine flux past the gland, whereas uptake of methionine was 30–40%. Total mammary uptake of cysteine was also lower than that of methionine when expressed as a percentage of whole body utilisation (6.5 and 14%, respectively). The uptake from the blood did not account for output in the milk for either cysteine or methionine. Both amino acids were highly conserved by the gland as shown by little release of any degraded constitutive protein amino acids and no evidence of oxidation products of either cysteine or methionine being released into the blood. Comparison of 35S activity in the milk from the infused and non-infused sides of the gland showed up to 10% trans-sulfuration of methionine to cysteine within the gland, none of which was exported in the venous drainage. Total ATP production by one side of the gland was 12.1 mol/day or 13 mmol/min.kg mammary tissue, of which 15% was required for gland protein synthesis. The experimental measurements from both the cysteine and methionine infusions were used to solve a model of gland amino acid uptake and partitioning. Modelling radioactivity of both amino acids in the blood, intracellular free pool, and milk protein suggested that a single intracellular pool cannot be the only source of amino acid for protein synthesis. The model also provides support for the hypothesis that a significant proportion of the uptake of at least some amino acids by the mammary gland is from intracellular hydrolysis of extracellularly derived peptides.

Whole body protein synthesis: studies with different amino acids in the rat

1989 ◽  
Vol 257 (5) ◽  
pp. E639-E646 ◽  
Author(s):  
C. Obled ◽  
F. Barre ◽  
D. J. Millward ◽  
M. Arnal
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Protein Turnover ◽  
Specific Radioactivity ◽  
Whole Body ◽  
Body Protein ◽  
Tissue Specific ◽  
Dose Method ◽  
Infusion Method

These studies were undertaken to determine to what extent constant infusion measurements and plasma sampling could provide sensible answers for rates of whole body protein turnover and also which amino acid would be the most representative probe of whole body protein turnover. Whole body protein synthesis rates were estimated in 70-g rats with L-[U-14C]threonine, L-[U-14C]lysine, L-[U-14C]tyrosine, L-[U-14C]phenylalanine, and L-[1-14C]leucine by either simultaneous tracer infusion of four amino acids or by injections of large quantities of 14C-labeled amino acids. In the infusion experiment, indirect estimates of whole body protein turnover based on free amino acid specific radioactivity and stochastic modeling were compared with direct measurement of the incorporation of the tracer into proteins. These two methods of analysis provided similar results for each amino acid, although in each case fractional synthesis rates were lower (by between 26 and 63%) when calculations were based on plasma rather than tissue specific radioactivity. With the flooding-dose method, whole body fractional protein synthesis rates were 41.4, 25.6, 31.1, and 31.4% with threonine, lysine, phenylalanine, and leucine, respectively. These values were similar to those obtained by the continuous infusion method using tissue specific radioactivity for threonine and lysine. For leucine, however, the flooding-dose method provided an intermediate value between the two estimates derived either from the plasma or the tissue specific radioactivity in the infusion method.(ABSTRACT TRUNCATED AT 250 WORDS)

The Anabolic Effect of Epidural Blockade Requires Energy and Substrate Supply

2002 ◽  
Vol 97 (4) ◽  
pp. 943-951 ◽  
Author(s):  
Thomas Schricker ◽  
Linda Wykes ◽  
Leopold Eberhart ◽  
Ralph Lattermann ◽  
Louise Mazza ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Glucose Production ◽  
Whole Body ◽  
Body Protein ◽  
Epidural Blockade ◽  
Thoracic Epidural ◽  
Parenteral Alimentation ◽  
Infusion Study ◽  
Intravenous Analgesia

Background The authors examined the hypothesis that continuous thoracic epidural blockade with local anesthetic and opioid, in contrast to patient-controlled intravenous analgesia with morphine, stimulates postoperative whole body protein synthesis during combined provision of energy (4 mg x kg(-1) x min(-1) glucose) and amino acids (0.02 ml x kg(-1) x min(-1) Travasol 10%, equivalent to approximately 2.9 g x kg(-1) x day(-1)). Methods Sixteen patients were randomly assigned to undergo a 6-h stable isotope infusion study (3 h fasted, 3 h feeding) on the second day after colorectal surgery performed with or without perioperative epidural blockade. Protein synthesis, breakdown and oxidation, glucose production, and clearance were measured by L-[1-(13)C]leucine and [6,6-(2)H(2) ]glucose. Results Epidural blockade did not affect protein and glucose metabolism in the fasted state. Parenteral alimentation decreased endogenous protein breakdown and glucose production to the same extent in both groups. Administration of glucose and amino acids was associated with an increase in whole body protein synthesis that was modified by the type of analgesia, i.e., protein synthesis increased by 13% in the epidural group (from 93.3 +/- 16.6 to 104.5 +/- 11.1 micromol x kg(-1) x h(-1) ) and by 4% in the patient-controlled analgesia group (from 90.0 +/- 27.1 to 92.9 +/- 14.8 micromol x kg(-1) x h(-1);P = 0.054). Conclusions Epidural blockade accentuates the stimulating effect of parenteral alimentation on whole body protein synthesis.

scholarly journals The effects of a combined implant of trenbolone acetate and oestradiol-17β on protein and energy metabolism in growing beef steers

1985 ◽  
Vol 54 (3) ◽  
pp. 681-694 ◽  
Author(s):  
G. E. Lobley ◽  
Alexmary Connell ◽  
G. S. Mollison ◽  
A. Brewer ◽  
C. I. HARRIS ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Total Energy ◽  
Protein Degradation ◽  
Whole Body ◽  
Beef Steers ◽  
Body Protein ◽  
Trenbolone Acetate ◽  
N Retention ◽  
Energy Retention

1. The effects on growth performance, energy and nitrogen retention, and leucine metabolism of a subcutaneous combined implant of 140 mg trenbolone acetate (TBA)+20 mg oestradiol-17β (OE) have been examined in Hereford × Friesian beef steers (280–520 kg). Comparisons were made both with the same animals before implantation and with untreated control animals maintained under similar physiological and nutritional conditions.2. Over a 10 week period the implanted steers showed an improvement in rate of live-weight gain (LWG) of 0.5–0.6 with an even greater proportional increase in N retention compared with control animals. Total energy retention was unaffected and thus the ratio, protein energy: total energy gain was 0.43 for implanted steers compared with 0.26 for untreated animals.3. Estimates of protein synthesis and protein oxidation were obtained from the specific radioactivities of blood free-leucine and exhaled carbon dioxide during continuous infusions of [1-14C]leucine. Whole-body protein synthesis, based on metabolic size, and amino acid fractional oxidation remained similar for control steers throughout the experiment. Steroid-treated steers showed a slight decline in synthesis which was significant (P < 0.05) at week + 5 post-implant while amino acid oxidation was significantly lower at weeks +2 (P < 0.01) and + 5 (P < 0.05) compared with control animals. The ratio, protein deposition: protein synthesis was 0.05 for control animals but 0.08–0.10 for steroid-treated animals after implantation.4. There was a slight decrease in urinary NT-methylhistidine elimination after implantation which suggested that muscle protein degradation may be reduced although the estimated decrease was insufficient to account for the total improvement in growth rate and N retention.5. The results suggest that for both control and treated steers, less than 0.5 of total urine N elimination was derived directly from tissue catabolism of protein and amino acids.6. The combined action of the exogenous steroids in the promotion of protein gain, primarily through a decrease in total protein degradation with little alteration of total energy retention, is compared with present understanding of the role of the endogenous sex hormones.

scholarly journals Available versus digestible amino acids – new stable isotope methods

2012 ◽  
Vol 108 (S2) ◽  
pp. S306-S314 ◽  
Author(s):  
Rajavel Elango ◽  
Crystal Levesque ◽  
Ronald O. Ball ◽  
Paul B. Pencharz
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Stable Isotope ◽  
Growing Pigs ◽  
The Body ◽  
Whole Body ◽  
Food Protein ◽  
Adult Humans

The nutritive value of food protein sources is dependent on the amino acid composition and the bioavailability of the nutritionally indispensable amino acids. Traditionally the methods developed to determine amino acid bioavailability have focused on intestinal absorption or digestibility, which is calculated as the percent of amino acid intake that does not appear in digesta or faeces. Traditional digestibility based methods do not always account for gut endogenous amino acid losses or absorbed amino acids which are unavailable due to the effect of heat processing and the presence of anti-nutritional factors, though methods have been developed to address these issues. Furthermore, digestibility based methods require the use of animal models, thus there is a need to developin vivomethods that can be applied directly in human subjects to identify the proportion of dietary amino acids which is bioavailable, or metabolically available to the body for protein synthesis following digestion and absorption. The indicator amino acid oxidation (IAAO) method developed in our laboratory for humans has been systematically applied to determine almost all indispensable amino acid requirements in adult humans. Oxidation of the indicator amino acid is inversely proportional to whole body protein synthesis and responds rapidly to changes in the bioavailability of amino acids for metabolic processes. Using the IAAO concept, we developed a newin vivomethod in growing pigs, pregnant sows and adult humans to identify the metabolic availability of amino acids in foods. The stable isotope based metabolic availability method is suitable for rapid and routine analysis in humans, and can be used to integrate amino acid requirement data with dietary amino acid availability of foods.

Whole body protein kinetics in women: effect of pregnancy and IDDM during anabolic stimulation

2000 ◽  
Vol 279 (5) ◽  
pp. E978-E988 ◽  
Author(s):  
Paul G. Whittaker ◽  
Choy H. Lee ◽  
Roy Taylor
Keyword(s):  
Amino Acids ◽  
Type 1 Diabetes ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Protein Metabolism ◽  
Whole Body ◽  
Protein Breakdown ◽  
Body Protein ◽  
In Pregnancy

The effects of pregnancy and type 1 diabetes [insulin-dependent diabetes mellitus (IDDM)] on protein metabolism are still uncertain. Therefore, six normal and five IDDM women were studied during and after pregnancy, using [13C]leucine and [2H5]phenylalanine with a hyperinsulinemic-euglycemic clamp and amino acid infusion. Fasting total plasma amino acids were lower in pregnancy in normal but not IDDM women (2,631 ± 427 vs. 2,057 ± 471 and 2,523 ± 430 vs. 2,500 ± 440 μmol/l, respectively). Whole body protein breakdown (leucine) increased in pregnancy [change in normal (ΔN) and IDDM women (ΔD) 0.59 ± 0.40 and 0.48 ± 0.26 g · kg−1 · day−1, both P < 0.001], whereas reductions in protein breakdown due to insulin/amino acids (ΔN −0.57 ± 0.19, ΔD −0.58 ± 0.20 g · kg−1 · day−1, both P < 0.001) were unaffected by pregnancy. Protein breakdown in IDDM women was not higher than normal, and neither pregnancy nor type 1 diabetes altered the insulin sensitivity of amino acid turnover. Nonoxidized leucine disposal (protein synthesis) increased in pregnancy (ΔN 0.67 ± 0.45, ΔD 0.64 ± 0.34 g · kg−1 · day−1, both P < 0.001). Pregnancy reduced the response of phenylalanine hydroxylation to insulin/amino acids in both groups (ΔN −1.14 ± 0.74, ΔD −1.12 ± 0.77 g · kg−1 · day−1, both P < 0.05). These alterations may enable amino acid conservation for protein synthesis and accretion in late pregnancy. Well-controlled type 1 diabetes caused no abnormalities in the regulation of basal or stimulated protein metabolism.

Postoperative Infusion of Amino Acids Induces a Positive Protein Balance Independently of the Type of Analgesia Used

2006 ◽  
Vol 105 (2) ◽  
pp. 253-259 ◽  
Author(s):  
Francesco Donatelli ◽  
Thomas Schricker ◽  
Giovanni Mistraletti ◽  
Francisco Asenjo ◽  
Piervirgilio Parrella ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Epidural Analgesia ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Whole Body ◽  
Protein Balance ◽  
Body Protein ◽  
Leucine Oxidation ◽  
Endogenous Glucose

Background Net loss of body protein is a prominent feature of the catabolic response to surgical tissue trauma. Epidural analgesia with hypocaloric dextrose has been demonstrated to attenuate leucine oxidation but was unable to make protein balance positive. The current study was set to determine whether an infusion of amino acids on the second day after colon surgery would revert the catabolic state and promote protein synthesis while maintaining glucose homeostasis in patients receiving epidural analgesia as compared with patient-controlled analgesia with morphine (PCA). Methods Sixteen patients undergoing colorectal surgery were randomly assigned to receive epidural blockade or PCA as analgesic techniques and underwent a 6-h stable isotope infusion study (3 h fasted, 3 h fed) on the second postoperative day. Whole body glucose kinetics and protein turnover were measured using [6,6-2H2]glucose and l-[1-13C]leucine as tracer. Results The infusion of amino acids caused a decrease in endogenous glucose rate of appearance in both groups (P &lt; 0.05), with greater changes in the PCA group (P &lt; 0.05). Administration of amino acids suppressed the appearance of leucine from protein breakdown in both groups (P &lt; 0.05), although the decrease was greater in the PCA group (P &lt; 0.05). Leucine oxidation increased in both groups (P &lt; 0.05), with greater change in the epidural group (P &lt; 0.05). Protein synthesis increased to the same extent in both groups (P &lt; 0.05). Protein balance became positive after the infusion of amino acids, and the effect was greater in the PCA group (P &lt; 0.05). Conclusions Infusion of amino acids decreased the endogenous glucose production and induced a positive protein balance independent of the type of anesthesia provided, although such effects were greater in the PCA group.

scholarly journals The effects of different dietary contents of protein on amino acid and glucose production and on the contribution of amino acids to gluconeogenesis in sheep

1971 ◽  
Vol 26 (2) ◽  
pp. 249-263 ◽  
Author(s):  
P. E. B. Reilly ◽  
E. J. H. Ford
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Intake ◽  
Glucose Production ◽  
Portal System ◽  
Total Amino Acid ◽  
Entry Rate ◽  
The Best Approximation ◽  
Rate Of Absorption ◽  
Total Glucose

1. Free amino acid entry rates, rates of portal uptake of amino acids and rates of glucose synthesis from amino acids have been measured during the continuous intravenous infusion of [U-14C]-labelled mixed amino acids in six sheep receiving diets that supplied different amounts of protein.2. In four of these sheep and in one other, total rates of glucose production have been measured using continuous intravenous infusions of [U-14C]-labelled glucose.3. A signiiicant correlation was found between total amino acid entry rate ( Y mg/min.kg) and daily protein intake ( X g/kg): Y = 2·14+ 1·38X (r = 0·878, 0·02 > P > 0·01).4. A significant correlation was found between the rate of absorption of amino acids into the portal system ( Y mg/min.kg) and the daily protein intake ( X g/kg): Y = 0·58 + 0·58X (r = 0·884, 0·02 > P > 0·01).5. A highly significant correlation was found between total glucose production rates ( Y mglmin. kg) and daily protein intake ( X g/kg): and daily protein intake ( X g/kg): Y = 2.14+ 1.38X (r = 0·878, 0·02 > P > 0·01). Y = 0·375f0·702X (r = 0·866, 0·005 > P > 0·001).6. The mean proportional contribution to total amino acid entry made by portal absorption was 33·5 f 1·8 yo (six animals).7. A significant correlation was found between the rate of glucose production from amino acids (Y mg/min.kg) and the rate of entry of amino acids ( X mg/min.kg): Y = 0-189X-0·414 ( r = 0·84, 0·01 > P > 0·005).8. The best approximation of the proportion of glucose derived from amino acids was 28·16 f 5·1 % (six animals).9. The specific radioactivities of amino acids in liver, kidney and muscle did not approach those found in plasma during infusions of [U-14C]-labelled mixed amino acids of up to 6·75 h.

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