scholarly journals Amino acid metabolism in the piglet: 2. Influence of fasting on plasma free amino acid concentration and in vivo oxidation of methionine, isoleucine and threonine

1976 ◽  
Vol 36 (2) ◽  
pp. 189-198 ◽  
Author(s):  
E. R. Chavez ◽  
H. S. Bayley

1. The influence of a 24 h fast on the concentrations of free amino acids in the plasma, and upon the oxidation rates of methionine, isoleucine and threonine was studied (using early weaned, 4-week-old piglets which were receiving a semi-purified diet.2. There was no change in the total concentration of the essential amino acids as a result of the 24 h fast: the concentration of the branched-chain amino acids increased, but the effect of this was offset by decreases in the concentrations of arginine, histidine, lysine, methionine and phenylalanine. There was a reduction in the concentration of the non-essential amino acids.3. The piglets received infusions of L-[1-14C]methionine, L-[U-14C]isoleucine and L-[U-14C]threonine, and the recovery of the label in carbon dioxide was determined. Less than 5% of the activity from methionine was recovered in the CO2 from the fed piglets, whereas 12% was recovered from the fasted piglets. The corresponding values with threonine were 11 and 19% but there was no effect of fasting on the recovery of the label from isoleucine in CO2.4. The initial dilution of a single dose of a labelled amino acid infused into the bloodstream depends on the plasma concentration of the amino acid. Nutritional regimens may effect the free amino acid concentration in the plasma. Thus comparisons based upon direct determination of activity recovered in CO2 from the labelled dose of an amino acid with animals on different nutritional regimens could be misleading, unless the differences in the concentrations of the amino acid in the plasma are considered.

1976 ◽  
Vol 36 (2) ◽  
pp. 219-230
Author(s):  
P. G. Lunn ◽  
R. G. Whitehead ◽  
B. A. Baker

1. Free amino acid concentrations in the plasma have been compared with those in liver and quadriceps muscle, in rats fed on diets containing 209 (control) and 31 (low-protein) g protein/kg. The effects of the low-protein diet on diurnal variations in these values were also measured.2. In the plasma, the total amino acid concentration was significantly lower in animals given the low-protein diet, at all times of day except 12.00 hours. In the liver, and to a lesser extent the muscle, total amino acid concentration was maintained.3. In the control animals, diurnal variation in the concentrations of both essential and non-essential amino acids was very similar in plasma, liver and muscle. In animals given the low-protein diet, although the same diurnal pattern was maintained for non-essential amino acids, that occurring among the essential amino acids had virtually disappeared.4. In plasma, the mean 24 h concentration of essential amino acids decreased from 24· mmol/l in control animals to only 1·29 mmol/l in the low-protein-fed animals. Concentrations in muscle and liver were reduced by a similar proportion (from 8·6 to 5·56 μmol/g and from 8·67 to 5·05 μmol/g respectively). Conversely the concentrations of non-essential amino acids in animals given the low-protein diet were increased in plasma (from 1·53 to 2·00 mmol/l), muscle (from 12·5 to 14·3 μmol/g), and liver (from 16·8 to 20·5 μmol/g), muscle showing the lowest increase.5. With the exceptions of lysine, threonine, cystine and tyrosine, the concentrations of all other essential amino acids were reduced more in liver than in muscle. The relationship between this and the failure to maintain plasma albumin concentrations is discussed.


2021 ◽  
Vol 33 (12) ◽  
pp. 2989-2992
Author(s):  
Borche Makarijoski ◽  
Gordana Dimitrovska ◽  
Vesna K. Hristova ◽  
Elena Joshevska ◽  
Mahmoud A. Abdelaziz Mahmoud ◽  
...  

The present work is focussed to determine the Macedonian white brined cheese’s free amino acid profile. Four variants of the Macedonian white brined cheese to analyze and determine free amino acid concentration; cheese samples define the Macedonian white brined cheese as a typical cheese. All free amino acids were specified, except the amino acid tyrosine. The detected amino acids in the tested cheese variants were present in different but approximate parameter values. The estimated essential free amino acids, the concentration of lysine was found highest in all examined samples with values from 26.40 ± 0.02 mg% to 28.20 ± 0.04 mg% and the concentration of threonine was the lowest from 3.19 ± 0.02 mg% to 3.32 ± 0.02 mg%). In the detected unessential free amino acids, the concentration of aspartic amino acid was highest in all the samples with values from 11.02 ± 0.05 mg% to 11.32 ± 0.03 mg% and the concentration of proline was at the lowest level from 4.16 ± 0.06 mg% to 4.22 ± 0.04 mg%.


2013 ◽  
Vol 57 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Adam Brodzki ◽  
Piotr Brodzki ◽  
Maria Szpetnar ◽  
Marcin R. Tatara

Abstract The aim of the study was to determine serum free amino acid concentration in male dogs suffering from benign and malignant perianal tumours. Serum concentrations of cysteic acid, glutamic acid, glutamine, aspartic acid, glycine, γ-aminobutyric acid, tryptophan, methionine, arginine, taurine, threonine, tyrosine, alanine, valine, isoleucine, and leucine were significantly changed in dogs suffering from benign and/or malignant tumours when compared to the control group (P<0.05). Serum concentration of serine, phenylalanine, lysine and histidine was not influenced in dogs with neoplastic disease (P>0.05). The evaluation of serum free amino acid concentration, has shown that threonine, glutamic acid, alanine, valine, isoleucine, leucine, γ-aminobutyric acid, and glycine have the highest diagnostic and prognostic value in dogs suffering from benign and malignant perianal tumours. Highly diagnostic and prognostic value in relation to benign tumour growth was also found while evaluating branched chain and acidic groups of amino acids. Serine, phenylalanine, lysine, and histidine, as well as alkaline amino acids were proved not to have diagnostic and prognostic value in dogs with the tumours. Thus, the evaluation of free amino acid concentration may serve diagnostic purposes and help in tumour malignancy differentiation. The elaborated experimental model may be used in further studies on neoplastic disease development and monitoring of applied treatment efficiency.


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