Effects on net plasma protein synthesis of removal of l-tryptophan or l-threonine from a complete amino acid mixture: studies in the isolated perfused rat liver

1971 ◽  
Vol 24 (6) ◽  
pp. 718-729 ◽  
Author(s):  
Leon L. Miller ◽  
Edmond E. Griffin
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Rat Liver ◽  
Plasma Protein ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Isolated Perfused Rat Liver ◽  
Perfused Rat Liver

Inhibition of Bile Flow in the Isolated Perfused Rat Liver by a Synthetic Parenteral Amino Acid Mixture: Associated Net Amino Acid Fluxes

Hepatology ◽  
1984 ◽  
Vol 4 (1) ◽  
pp. 69-73 ◽  
Author(s):  
Martin F. Graham ◽  
Anthony S. Tavill ◽  
Thomas C. Halpin ◽  
Loizos N. Louis
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Bile Flow ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Isolated Perfused Rat Liver ◽  
Perfused Rat Liver

Effect of Dietary Protein and Amino Acid Mixture on Protein Synthesis in vitro in Rat Liver

1974 ◽  
Vol 16 (6) ◽  
pp. 325-336 ◽  
Author(s):  
Alexandra von der Decken ◽  
Per T. Omstedt
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Rat Liver ◽  
Dietary Protein ◽  
Amino Acid Mixture ◽  
Acid Mixture

An abundant supply of amino acids enhances the metabolic effect of exercise on muscle protein

1997 ◽  
Vol 273 (1) ◽  
pp. E122-E129 ◽  
Author(s):  
G. Biolo ◽  
K. D. Tipton ◽  
S. Klein ◽  
R. R. Wolfe
Keyword(s):  
Amino Acids ◽  
Blood Flow ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Protein Kinetics ◽  
Amino Acid Infusion

Six normal untrained men were studied during the intravenous infusion of a balanced amino acid mixture (approximately 0.15 g.kg-1.h-1 for 3 h) at rest and after a leg resistance exercise routine to test the influence of exercise on the regulation of muscle protein kinetics by hyperaminoacidemia. Leg muscle protein kinetics and transport of selected amino acids (alanine, phenylalanine, leucine, and lysine) were isotopically determined using a model based on arteriovenous blood samples and muscle biopsy. The intravenous amino acid infusion resulted in comparable increases in arterial amino acid concentrations at rest and after exercise, whereas leg blood flow was 64 +/- 5% greater after exercise than at rest. During hyperaminoacidemia, the increases in amino acid transport above basal were 30-100% greater after exercise than at rest. Increases in muscle protein synthesis were also greater after exercise than at rest (291 +/- 42% vs. 141 +/- 45%). Muscle protein breakdown was not significantly affected by hyperminoacidemia either at rest or after exercise. We conclude that the stimulatory effect of exogenous amino acids on muscle protein synthesis is enhanced by prior exercise, perhaps in part because of enhanced blood flow. Our results imply that protein intake immediately after exercise may be more anabolic than when ingested at some later time.

scholarly journals Carbohydrate formation from various precursors in neonatal rat liver

1968 ◽  
Vol 110 (4) ◽  
pp. 725-731 ◽  
Author(s):  
R. G. Vernon ◽  
Susan W. Eaton ◽  
D G Walker
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Neonatal Period ◽  
Casein Hydrolysate ◽  
Amino Acid Mixture ◽  
Neonatal Rat ◽  
Acid Mixture ◽  
Hepatic Gluconeogenesis ◽  
Threonine Dehydratase ◽  
Serine Dehydratase

1. Measurements of the net synthesis of glucose plus glycogen from various precursors in slices of glycogen-depleted livers from rats at various stages of development indicated an increase in the gluconeogenic capacity after birth with l-lactate, oxaloacetate, a casein hydrolysate, l-serine, l-threonine, l-alanine and glycerol as substrates. 2. The highest rates of incorporation of 14C-labelled precursors into glucose plus glycogen in slices of normal livers of rats of various ages were observed in such tissue preparations from neonatal animals for an amino acid mixture, l-alanine, l-serine and l-threonine. 3. The activities of rat hepatic l-serine dehydratase and l-threonine dehydratase increase rapidly after birth and show maxima about 20 days later. 4. The results provide further evidence of the increased capacity for hepatic gluconeogenesis in the neonatal period and suggest various sites of regulation of the process.

scholarly journals Cell swelling increases bile flow and taurocholate excretion into bile in isolated perfused rat liver

1992 ◽  
Vol 281 (3) ◽  
pp. 593-595 ◽  
Author(s):  
C Hallbrucker ◽  
F Lang ◽  
W Gerok ◽  
D Häussinger
Keyword(s):  
Bile Acid ◽  
Amino Acid ◽  
Cell Volume ◽  
Rat Liver ◽  
Bile Flow ◽  
Cell Swelling ◽  
Isolated Perfused Rat Liver ◽  
Perfused Rat Liver ◽  
Volume Changes ◽  
Close Relationship

The effects of aniso-osmotically and amino-acid-induced cell-volume changes on bile flow and biliary taurocholate excretion were studied in isolated perfused rat liver. With taurocholate (100 microM) in the influent perfusate, hypo-osmotic exposure (225 mosmol/l) increased taurocholate excretion into bile and bile flow by 42 and 27% respectively, whereas inhibition by 32 and 47% respectively was observed after hyperosmotic (385 mosmol/l) exposure. The effects of aniso-moticity on taurocholate excretion into bile was observed throughout aniso-osmotic exposure, even after completion of volume-regulatory ion fluxes and were fully reversible upon re-exposure to normo-osmotic media. Hypo-osmotic cell swelling (225 mosmol/l) increased the Vmax. of taurocholate translocation from the sinusoidal compartment into bile about 2-fold. Also, cell swelling induced by glutamine and glycine stimulated both bile flow and biliary taurocholate excretion. There was a close relationship between the aniso-osmotically and amino-acid-induced change of cell volume and taurocholate excretion into bile. The data suggest that liver cell volume plays an important role in regulating bile-acid-dependent bile flow and biliary taurocholate excretion.

Endotoxemia reduces skeletal muscle protein synthesis in neonates

2002 ◽  
Vol 283 (5) ◽  
pp. E909-E916 ◽  
Author(s):  
Renan A. Orellana ◽  
Pamela M. J. O'Connor ◽  
Hanh V. Nguyen ◽  
Jill A. Bush ◽  
Agus Suryawan ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Interleukin 1 ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Skeletal Muscle Protein ◽  
Skeletal Muscle Protein Synthesis

Protein synthesis in skeletal muscle is reduced by as much as 50% as early as 4 h after a septic challenge in adults. However, the effect of sepsis on muscle protein synthesis has not been determined in neonates, a highly anabolic population whose muscle protein synthesis rates are elevated and uniquely sensitive to insulin and amino acid stimulation. Neonatal piglets ( n = 10/group) were infused for 8 h with endotoxin [lipopolysaccharide (LPS), 0 and 10 μg · kg−1 · h−1]. Plasma amino acid and glucose concentrations were kept at the fed level by infusion of dextrose and a balanced amino acid mixture. Fractional protein synthesis rates were determined by use of a flooding dose of [3H]phenylalanine. LPS infusion produced a septic-like state, as indicated by an early and sustained elevation in body temperature, heart rate, and plasma tumor necrosis factor-α, interleukin-1, cortisol, and lactate concentrations. Plasma levels of insulin increased, whereas glucose and amino acids decreased, suggesting the absence of insulin resistance. LPS significantly reduced protein synthesis in longissimus dorsi muscle by only 11% and in gastrocnemius by only 15%, but it had no significant effect in masseter and cardiac muscles. LPS increased protein synthesis in the liver (22%), spleen (28%), kidney (53%), jejunum (19%), diaphragm (21%), lung (50%), and skin (13%), but not in the stomach, pancreas, or brain. These findings suggest that, when substrate supply is maintained, skeletal muscle protein synthesis in neonates compared with adults is relatively resistant to the catabolic effects of sepsis.

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