RELATIONSHIP BETWEEN DIETARY PROTEIN CONTENT AND PLASMA AMINO ACIDS IN SHEEP FED PURIFIED DIETS

1973 ◽  
Vol 53 (3) ◽  
pp. 455-464
Author(s):  
A. CECYRE ◽  
G. M. JONES ◽  
J.-M. GAUDREAU
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Time Intervals ◽  
Dietary Nitrogen ◽  
Low Protein ◽  
Limiting Amino Acid ◽  
Nonessential Amino Acids ◽  
Amino Acid Concentrations

Semipurified diets, varying in crude protein (CP) content (6, 10, 15, and 22% CP), were each fed to one wether and plasma amino acid (PAA) concentrations were determined at 0, 15, 30, 60, 120, 240, and 360 min postfeeding. Total essential amino acid concentrations for the 6, 10, and 15% CP rations were 47.2, 76.4, and 72.9 μmol/ml, while nonessential amino acids totalled 88.3, 110.0, and 104.9 μmol/ml, respectively. In general, PAA concentrations were depressed by the low protein diet, except for glycine, which was elevated, and threonine and alanine, which were not affected. PAA concentrations gradually decreased with time after feeding. There was no evident relationship between PAA levels and amount of feed consumed at these time intervals. Lysine was probably the most limiting amino acid, based upon PAA concentrations on the low protein diet compared to average PAA levels for all diets. PAA concentrations reflected dietary nitrogen content. The results suggest that PAA levels were not involved in the regulation of voluntary intake when the diet contained sufficient protein to meet the requirements of the animal.

scholarly journals The relative effects of a low-protein-high-carbohydrate diet on the free amino acid composition of liver and muscle

1976 ◽  
Vol 36 (2) ◽  
pp. 219-230
Author(s):  
P. G. Lunn ◽  
R. G. Whitehead ◽  
B. A. Baker
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Acid Concentration ◽  
Free Amino ◽  
Essential Amino Acids ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Total Amino Acid ◽  
Low Protein

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.

Plasma Insulin and Amino Acid Concentrations in Rats Given an Adequate or Low Protein Diet

1973 ◽  
Vol 103 (5) ◽  
pp. 720-729 ◽  
Author(s):  
Vernon R. Young ◽  
Gaston Vilaire ◽  
Paul M. Newberne ◽  
Robert B. Wilson
Keyword(s):  
Amino Acid ◽  
Plasma Insulin ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Low Protein ◽  
Amino Acid Concentrations

scholarly journals The regulation of protein synthesis in the liver of rats. Mechanisms of dietary amino acid control in the immature animal

1968 ◽  
Vol 107 (5) ◽  
pp. 615-623 ◽  
Author(s):  
R. W. Wannemacher ◽  
W. K. Cooper ◽  
M. B. Yatvin
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Specific Radioactivity ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Deficient Diet ◽  
Low Protein ◽  
Rna Content ◽  
Cytoplasmic Rna

Weanling (23-day-old) rats were fed either on an amino acid-deficient diet (6% of casein, which in effect represents an ‘amino acid-deficient’ diet) or on a diet containing an adequate amount of protein (18% of casein) for 28 days. The hepatic cells from the animals fed on the low-protein diet were characterized by low amino acid content, almost complete inhibition of cell proliferation and a marked decrease in cell volume, protein content and concentration of cytoplasmic RNA compared with cells from control rats. The lower concentration of cytoplasmic RNA was correlated with a decreased ribosomal-RNA content, of which a larger proportion was in the form of free ribosomes. The protein-synthetic competence and messenger-RNA content of isolated ribosomes from liver cells of protein-deprived animals were 40–50% of those noted in controls. At 1hr. after an injection of radioactive uridine, the specific radioactivity of liver total RNA was greater in the group fed on the low-protein diet, but the amount of label that was associated with cytoplasmic RNA or ribosomes was significantly less than that noted in control animals. From these data it was concluded that dietary amino acids regulate hepatic protein synthesis (1) by affecting the ability of polyribosomes to synthesize protein and (2) by influencing the concentration of cytoplasmic ribosomes. It is also tentatively hypothesized that the former process may be directly related to the concentration of cellular free amino acids, whereas the latter could be correlated with the ability of newly synthesized ribosomal sub-units to leave the nucleus.

scholarly journals Physiological concentration of amino acids regulates insulin-like-growth-factor-binding protein 1 expression

1998 ◽  
Vol 334 (1) ◽  
pp. 147-153 ◽  
Author(s):  
Céline JOUSSE ◽  
Alain BRUHAT ◽  
Marc FERRARA ◽  
Pierre FAFOURNOUX
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Growth Factor ◽  
Hepg2 Cells ◽  
Binding Protein ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Insulin Like Growth Factor ◽  
Low Protein ◽  
Igf I

Protein undernutrition is characterized by growth failure in young growing animals. Current evidence suggests that biosynthesis of insulin-like growth factor (IGF)-I and IGF-binding protein 1 (IGFBP-1) are key control points for nutritional regulation of growth. Here we examined the role of amino acid limitation in regulating the IGFBP-1 expression in the hepatic cell line. Our data show that leucine limitation strongly induces IGFBP-1 without affecting IGF-I and IGF-II expression in human HepG2 cells and in isolated rat hepatocytes. Depletion of arginine, cystine and all essential amino acids leads to induction of IGFBP-1 mRNA and protein expression in a dose-dependent manner. IGFBP-1 expression is significantly induced by leucine concentration in the range of that observed in the blood of rats fed a low-protein diet or in humans affected by kwashiorkor. Moreover, treatment of HepG2 cells with amino acids at a concentration reproducing the amino acid concentration found in portal blood of rats fed a low-protein diet leads to a significantly higher expression of IGFBP-1. These data represent the first demonstration that an amino acid limitation, as occurs during dietary protein deficiency, induces IGFBP-1 expression in hepatic cells. Therefore, amino acids by themselves can play, in concert with hormones, an important role in the control of gene expression.

Discrimination by Rhesus Monkeys of Diets Containing Supplemental Amino Acids

1975 ◽  
Vol 41 (3) ◽  
pp. 683-689
Author(s):  
Samuel N. Craddock ◽  
Arthur J. Riopelle
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rhesus Monkeys ◽  
Normal Diet ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Low Protein ◽  
Egg Protein ◽  
Protein Diets ◽  
Whole Egg

Following an opportunity to demonstrate a preference for water with or without the addition of the amino acid isoleucine, methionine, phenylalanine, or tryptophan at a concentration proportional to that in whole egg protein, 9 monkeys were subjected on 4 occasions to a 7-day experimental week when they received an isocaloric diet containing only one-fourth the amount of protein of their normal diet. An identical low-protein diet supplemented with one of the above amino acids, again at a concentration proportional to that in egg, was presented for an equivalent period during the experimental week and the amounts consumed of each diet were compared. Ss failed to exhibit a preference or an aversion for water supplemented with any of the amino acids; however, all low-protein diets supplemented with an amino acid were consumed in greater quantities than a low-protein diet lacking a supplement. On Days 6 and 7 of the experimental weeks when protein depletion was most severe, Ss significantly ( p < .05) preferred the diet supplemented with isoleucine to a diet lacking the supplement.

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