Variations in the concentrations of free amino acids in the plasma of the dairy cow at parturition

1972 ◽  
Vol 39 (3) ◽  
pp. 355-364 ◽  
Author(s):  
R. Verbeke ◽  
E. Roets ◽  
G. Peeters
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino ◽  
Milk Protein ◽  
Sampling Period ◽  
Aminobutyric Acid ◽  
Amino Acid Utilization ◽  
Amino Acid Levels ◽  
The Mean ◽  
Peak Value

SummaryThe plasma levels of individual amino acids were studied in 6 dairy cows from 4 days before to 3 days after calving. During this sampling period, the concentrations of 13 amino acids showed significant changes. The levels of several amino acids were depressed markedly in the sample collected immediately before calving. Following parturition, the concentration of most amino acids gradually returned to values obtained 3 days before calving. The glutamine and alanine contents of the plasma rose to a peak value 1 day after calving and subsequently decreased. The mean concentrations of glycine and α-aminobutyric acid did not change before parturition but rose significantly thereafter. These observations are discussed in terms of amino-acid utilization for milk protein synthesis and gluconeogenesis at the onset of lactation. The changes in plasma amino acid levels appear to be synchronized with those reported for prolactin and progesterone in the 24 h before parturition. This may indicate an important influence of both hormones on the lactogenic process in the cow. The highly significant correlations obtained between the concentrations of 14 individual amino acids are discussed.

Effect of diet and infusion of volatile fatty acids into the rumen on the concentration of plasma free amino acids in sheep

1982 ◽  
Vol 48 (3) ◽  
pp. 519-526 ◽  
Author(s):  
J. R. Mercer ◽  
E. L. Miller
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino ◽  
Volatile Fatty Acids ◽  
Plasma Concentrations ◽  
Essential Amino Acids ◽  
Protein Nitrogen ◽  
Post Infusion ◽  
Limiting Amino Acid ◽  
The Mean

1. The effect of supplementing barley diets with urea (U), extracted decorticated groundnut meal (GNM) or Peruvian fish meal (PFM) on plasma free amino acid concentrations in sheep have been examined and the first limiting amino acid has been indicated by measuring the changes in the concentration of the plasma essential amino acids (PEAA) during a rumen infusion of a volatile fatty acid (VFA) mixture.2. Three wethers fitted with rumen and re-entrant duodenal cannulas were given isonitrogenous, isoenergetic diets containing (g/kg dry matter (DM)) U 20, GNM 106 or PFM 78, the crude protein (nitrogen × 6.25) contents being 139, 145 and 148 respectively. The sheep were fed hourly, the mean daily dm intake being 0.634 kg.3. Plasma concentrations of valine, threonine, lysine, isoleucine and leucine were linearly related to their concentrations in duodenal digesta.4. A VFA mixture was infused into the rumen for 6 h to supply (mmol/min) acetate 1.47, propionate 0.22 and n-butyrate 0.27. Blood samples were taken 6 h before, during and 12 h after the end of the infusion.5. The concentration of all PEAA decreased relative to the pre-infusion and post-infusion controls but there were no significant differences between diets.6. The mean decreases in concentration averaged over all three diets showed that the decrease in concentration of methionine (41.5%) was far greater than for any other essential amino acid suggesting that under these conditions methionine was the first limiting amino acid.

EFFECT OF CORTISOL TREATMENT ON FREE AMINO ACID LEVELS IN RATS

1973 ◽  
Vol 59 (1) ◽  
pp. 57-63 ◽  
Author(s):  
W. DE LOECKER ◽  
M. L. STAS
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Protein Turnover ◽  
Free Amino Acids ◽  
Free Amino ◽  
Experimental Period ◽  
Amino Acid Levels ◽  
Amino Acid Concentrations

SUMMARY Changes in the concentrations of free amino acids in intracellular fluids and blood plasma were measured in rats treated with cortisol. Increasing age raised the concentrations of free amino acids in plasma, while in liver, with the exception of glycine and alanine, decreased concentrations were observed. Cortisol treatment reduced free amino acid levels in plasma and liver which suggested a progressive catabolism of body proteins and increased protein synthesis in the liver. In skeletal muscle of control rats the free amino acid concentrations increased during the experimental period. Cortisol increased the concentration of certain amino acids and decreased that of others due to an increased protein turnover in muscle.

A COMPARISON OF THE EFFECT OF DIETARY FAT AND CARBOHYDRATE ON FREE AMINO ACIDS IN THEBLOOD PLASMA OF CHICKS

1967 ◽  
Vol 45 (2) ◽  
pp. 225-234 ◽  
Author(s):  
Tsang-Cheng Shao ◽  
D. C. Hill
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Dietary Fat ◽  
Free Amino Acids ◽  
Free Amino ◽  
Plasma Amino Acid ◽  
Considerable Time ◽  
Lower Plasma ◽  
Amino Acid Levels ◽  
Plasma Free Amino Acids

As previously reported, an increased concentration of plasma free amino acids, particularly lysine and threonine, was found when chicks were fasted for 24 hours. This increase was suppressed where a nonprotein diet was fed. Dextrose as the chief energy source in the nonprotein diet was more effective than shortening or lard in this respect. However, the degree to which the two energy sources differed was less where birds were adapted to the utilization of fat by feeding a diet rich in fat for a considerable time before making the comparison. Insulin administration to fasted chicks was found to lower plasma amino acid levels. The possible influence of interrelationships among dextrose, fat, and insulin on plasma amino acid levels is discussed.

Intracellular free amino acid patterns in duodenal and colonic mucosa

1990 ◽  
Vol 36 (2) ◽  
pp. 378-381 ◽  
Author(s):  
G Ollenschläger ◽  
K Langer ◽  
H M Steffen ◽  
M Schrappe-Bächer ◽  
H Schmitt ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino ◽  
Dry Weight ◽  
Essential Amino Acids ◽  
Medical Patients ◽  
The Mean ◽  
First Time ◽  
Duodenal Biopsies ◽  
Hiv Negative

Abstract We report for the first time the concentrations of free amino acids in human intestinal biopsies obtained by routinely performed endoscopy. We studied 15 medical patients with no changes of the mucosa and six HIV-infected persons with duodenitis. The mean (and SD) sum of all amino acids, taurine excepted, was 61.9 (5.4) mmol/kg dry weight in duodenal biopsies of HIV-negative subjects (n = 11) and 82.9 (0.6) mmol/kg in colonic specimens: 50% (44%) of the total (minus taurine) consisted of aspartate and glutamate and 14% (12%), of the essential amino acids. The relative amino acid pattern in duodenum and colon differed completely from that for muscle: aspartate was fourfold higher; glutamate, phenylalanine, glycine, valine, leucine, and isoleucine were about twofold higher. In contrast, glutamine amounted only to 4% (duodenum) to 14% (colon) of muscle glutamine. In duodenal biopsies of the HIV-infected persons, we found significantly (P less than 0.01, except glutamine: P less than 0.025) increased concentrations of glutamate (24.1 vs 17 mmol/kg dry weight), ornithine (1.4 vs 0.4), valine (2.2 vs 1.7), and glutamine.

Incorporation of carbon atoms from glucose into free amino acids in brain under normal and altered conditions

1970 ◽  
Vol 48 (3) ◽  
pp. 228-235 ◽  
Author(s):  
Y. Yoshino ◽  
K. A. C. Elliott
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Acid Level ◽  
Specific Activity ◽  
Specific Radioactivity ◽  
Aminobutyric Acid ◽  
Aminooxyacetic Acid

The time course of entry of radioactive carbon from intravenously administered [U-14C]-glucose into free amino acids in the brains of rats has been studied using an automatic amino acid analyzer coupled through a flow cell with a scintillation counter. Radioactivity appeared rapidly in alanine, aspartic acid, glutamic acid, glutamine, and γ-aminobutyric acid as previously shown, and in an unknown ninhydrin-positive substance present in very small amount. Urea, serine, and glycine became slightly radioactive. Four hours after giving the radioactive glucose, the specific activity in all soluble substances was low. In pentobarbital anesthesia, specific radioactivity was increased in alanine and decreased in γ-aminobutyric acid, aspartic and glutamic acids, and glutamine. A high proportion of radioactivity remained in glucose. Under hypoxia, alanine increased in amount but decreased in specific activity, and the specific activities of the other strongly labelled amino acids decreased. The proportion of the total radioactivity found in glucose and lactate increased. During picrotoxin and pentylenetetrazol convulsions, changes occurred which were similar to those under hypoxia. After aminooxyacetic acid administration, the well-known great increase in γ-aminobutyric acid level was found to be accompanied by a decrease in glutamate and also in aspartic acid and alanine, indicating inhibition of the three transaminases concerned. The previously observed brief rapid postmortem increase in the amount of γ-aminobutyric acid was confirmed; alanine also increased briefly but no other amino acid did so. The increased γ-aminobutyric acid had the same specific radioactivity as the original but the extra alanine was less radioactive than the original. When the γ-aminobutyric acid level had been increased by administration of aminooxyacetic acid, the rapid postmortem increase did not occur.

Nitrogen digestion in forage-fed sheep with and without intraruminal propionate infusion

1993 ◽  
Vol 120 (1) ◽  
pp. 107-114 ◽  
Author(s):  
C. J. Seal ◽  
D. S. Parker ◽  
J. Balcells ◽  
J. L. Mole
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Gastrointestinal Tract ◽  
Propionic Acid ◽  
Nitrogen Balance ◽  
Free Amino ◽  
Alternative Energy ◽  
Total Amino Acid ◽  
Acid Infusion ◽  
Amino Acid Levels

SUMMARYNitrogen balance and flow of nitrogen along the gastrointestinal tract were determined in growing wether sheep fed a dried grass pellet diet with or without intraruminal propionic acid infusion. Plasma free amino acid and glucose concentrations tended to be higher in peripheral blood of animals receiving propionate (P < 0·10). Overall total nitrogen and amino acid digestibilities and apparent digestibilities of each fraction along the digestive tract were not affected by infusion of propionic acid. The contribution of microbial amino acids to total amino acid flow in the duodenum measured using purine bases as the microbial marker averaged 0·49 and was not affected by propionic acid infusion. It is suggested that changes in circulating amino acid levels arise from reduced utilization of luminal amino acids by gastrointestinal tissues due to the increased availability of alternative energy-yielding substrates.

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