Isolation-Perfusion of Ovine Hind Limbs. III. Perfusate Lysine Levels

Ja, Boling; Jc, Willard; Wr, Burris

doi:10.2527/jas1977.454832x

Cited by 2 publications

(4 citation statements)

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“…This suggests that amino acids were being continually removed from the perfusate while plasma levels of lysine were being maintained by release of amino acids from muscle amino acid pools. This is supported by previously published research from our laboratory (Boling et al, 1977), and others (Christensen, 1964).…”

Section: ?Ssupporting

confidence: 79%

“…As expected, perfusate urea N levels were unaffected by time or treatment (average concentrations were 13.6, 12.5 and 13.2 mg/dl for control, low-and high-stimula-tion groups, respectively). Toxic effects of accumulated ammonia on muscle metabolism were not observed in this or earlier experiments (Cross et al, 1974a,b;Boling et al, 1977).…”

Section: Resultscontrasting

confidence: 38%

“…Cross et al (1974a) used 14C-leucine and observed approximately 13% TCA precipitable radioactivity. Boling et al (1977) found that approximately 20% of total radioactivity was precipitated by TCA when 14Clysine was used. This suggests that specific or nonspecific amino acid carriers rapidly bind substantial portions of amino acids for transport by the blood.…”

Section: ?Smentioning

confidence: 99%

“…Extrahepatic influences of muscle activity on amino acid metabolism in ruminants have not been reported. Studies from this laboratory have shown that the isolated-perfused hind limbs of sheep provide an adequate system for assessing amino acid uptake and metabolism by ruminant muscle (Cross et al, 1974a,b;Boling et al, 1977). The objective of this experiment was to study glucose and amino acid metabolism in perfused ovine hind limbs as affected by level of muscular activity.…”

Section: Introductionmentioning

confidence: 99%

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Isolation-Perfusion of Ovine Hind Limbs. IV. Effects of Level of Activity on Amino Acid and Glucose Metabolism

Ww¹,

Lc²,

Ja³

et al. 1984

Journal of Animal Science

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Twenty-one wether lambs averaging 30.0 kg were utilized in a study to determine the influence of level of muscular activity (via electrical stimulation) on metabolism of amino acids and glucose of isolated-perfused hind limbs. Treatments consisted of: (1) control, (2) low electrical stimulation and (3) high electrical stimulation. Mean perfusion flow rate was unaffected by treatment or time of perfusion. Perfusion pressure and hematocrit were increased (P less than .05) by stimulation. Glucose levels decreased from a pretreatment average of 44.7 to 41.3, 26.8 and 20.0 mg/dl for treatments 1 to 3, respectively. Lactic acid levels increased from the pretreatment mean of 37.7 to 46.7, 63.8 and 69.4 mg/dl, respectively. Plasma-free fatty acids were utilized from the perfusate at .84, .76 and .68 meq X liter-1 X min-1, respectively. Perfusate urea N levels were unaffected by treatment or time of sampling, but perfusate ammonia levels increased in all treatments (ammonia levels for treatments 1 to 3 increased by .50, 1.09 and 1.47 mg/dl, respectively). Perfusate amino acid changes suggested a flux of some amino acids from muscle to perfusate due to electrical stimulation, but perfusate branched chain amino acid concentrations decreased in all treatment groups. Fifty microcuries of 14C-lysine were included in the initial perfusate. Total perfusate radioactivity in all treatments declined with time, reflective of lysine uptake by the muscle. Total perfusate lysine concentration changed less markedly, suggesting that muscle is contributing to maintenance of plasma amino acid levels.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: ?Ssupporting

confidence: 79%

Section: Resultscontrasting

confidence: 38%

Section: ?Smentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Isolation-Perfusion of Ovine Hind Limbs. IV. Effects of Level of Activity on Amino Acid and Glucose Metabolism

Ww¹,

Lc²,

Ja³

et al. 1984

Journal of Animal Science

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Metabbolism of perfused ruminant muscle

Coward

Buttery

1982

J. Agric. Sci.

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Substrate and nitrogen metabolism of ruminant muscle was studied in vitro using a perfused sheep hemidiaphragm preparation. Glucose, acetate, propionate and butyrate were taken up by the perfused muscle at a constant rate over 2 h. Rate of acetoacetate uptake declined over the perfusion period. Net production of 3-hydroxybutyrate over the perfusion period was observed.Release of alanine and glycine by the perfused muscle could not be accounted for by protein breakdown, implicating muscle as a site of synthesis of these amino acids. The perfused muscle metabolized aspartate and arginine to a considerable extent, but the branched-chain amino acids only to a small extent. Only a small proportion, approximately 5 %, of the alanine produced by the perfused muscle was derived from glucose.In the presence of amino acids, at twice the concentration found in plasma, and insulin, some amino acids showed a net uptake by the diaphragm but when cysteine was omitted from the perfusate, all amino acids with the exception of arginine showed a net output. Evidence was obtained that protein synthesis was reduced in the absence of cysteine. The output of NT methylhistidine by the preparation was much higher than could be accounted for by estimates of protein breakdown using isotope dilution techniques. These data are, however, consistent with the view that NT methylhistidine is not a good index of muscle protein breakdown in sheep.

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Isolation-Perfusion of Ovine Hind Limbs. III. Perfusate Lysine Levels

Cited by 2 publications

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Isolation-Perfusion of Ovine Hind Limbs. IV. Effects of Level of Activity on Amino Acid and Glucose Metabolism

Isolation-Perfusion of Ovine Hind Limbs. IV. Effects of Level of Activity on Amino Acid and Glucose Metabolism

Metabbolism of perfused ruminant muscle

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