Effects of branched chain amino acids, pyruvate, or ketone bodies on the free amino acid pool and release from brain cortex slices of normal and streptozotocindiabetic rats

1987 ◽  
Vol 12 (1) ◽  
pp. 1-7 ◽  
Author(s):  
G. Palaiologos ◽  
H. Philippidis ◽  
H. Chomatas ◽  
D. Iakovou ◽  
A. Linardou
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino ◽  
Brain Cortex ◽  
Ketone Bodies ◽  
Branched Chain Amino Acids ◽  
Free Amino Acid Pool ◽  
Brain Cortex Slices ◽  
Cortex Slices ◽  
Branched Chain

AMINO ACID TRANSPORT IN BRAIN CORTEX SLICES: II. COMPETITION BETWEEN AMINO ACIDS

1962 ◽  
Vol 40 (11) ◽  
pp. 1591-1602 ◽  
Author(s):  
P. N. Abadom ◽  
P. G. Scholefield
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rat Brain ◽  
Amino Acid Transport ◽  
Brain Cortex ◽  
Transport Systems ◽  
Acid Transport ◽  
Inhibitory Effects ◽  
Brain Cortex Slices ◽  
Cortex Slices

Evidence is presented which indicates that several amino acid transport systems are present in rat brain cortex slices, each with its own specificity with regard to substrate and with regard to amino acids which produce inhibitory effects. The nature of these inhibitory effects may be either direct (competition for a limiting number of sites) or indirect (as they are when glutamate or aspartate cause a decrease in the ATP content).Comparison of the specificities of the glycine transport systems present in rat brain cortex slices and in Ehrlich ascites carcinoma cells indicates that these two systems have little in common and the relation of this finding to the structural requirements necessary for chemotherapeutic activity is discussed.

scholarly journals Effects of ketone bodies on amino acid metabolism in isolated rat diaphragm

1976 ◽  
Vol 154 (3) ◽  
pp. 709-716 ◽  
Author(s):  
G Palaiologos ◽  
P Felig
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Acid Metabolism ◽  
Ketone Bodies ◽  
Branched Chain Amino Acids ◽  
Tissue Content ◽  
Constant Rate ◽  
Branched Chain ◽  
Glutamine Production

1. Diaphragms from 48h-starved rats were incubated in Krebs-Ringer bicarbonate medium at 37degreesC for 30min and then transferred into new medium and incubated for 1, 2 and 3 h. 2. The amount of free amino acids found at the end of each time of incubation was larger than the amount at the beginning of incubation, indicating that in this system proteolysis is prevailing. 3. The diaphragms was releasing mainly alanine and glutamine into the incubation medium. 4. Within the periods of incubation the release and metabolism of free amino acids was proceeding at a constant rate. 5. Addition of sodium DL-3-hydroxybutyrate decreased the tissue content of several amino acids, among which were tyrosine and phenylalanine, suggesting that proteolysis was decreased by ketone bodies. 6. In the presence of glucose (10mM) and branched-chain amino acids (0.5mM), sodium DL-3-hydroxybutyrate at concentrations of 4 or 6 mM resulted in 30% decrease in tissue alanine content and a 20% decline in alanine release. Release of taurine and glutamine was decreased by 19 and 16% respectively with 6 mM-sodium DL-3-hydroxybutyrate. Addition of sodium acetoacetate (1-3mM) also resulted in a 20-35% decrease in tissue content of alanine, glutamine and taurine and in a 15-24% decrease of alanine and glutamine release. Smaller decreases (less than 15%) in the release of glycine, threonine, proline, serine and aspartate were also observed in the presence of sodium DL-3-hydroxybutyrate or sodium acetoacetate. 7. Substitution of pyruvate (1.0mM) for glucose in the presence of acetoacetate restored alanine and glutamine production to control values. In the presence of acetoacetate, pyruvate also increased the tissue content of aspartate by 77% and decreased the tissue content of glutamate by 30%. 8. It is suggested that in diaphragms from starved rats, ketone bodies (a) in the absence of other substrates inhibit protein catabolism and (b) in the presence of glucose and branched-chain amino acids decrease alanine and glutamine production, by inhibiting glycolysis.

scholarly journals Effects of amino acid preparations on the amino acid composition of the liver of rats under subchronic alcohol intoxication

2020 ◽  
Vol 17 (3) ◽  
pp. 337-345
Author(s):  
Yu. E. Razvodovsky ◽  
V. Yu. Smirnov ◽  
I. N. Semenenya
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Free Amino Acids ◽  
Free Amino ◽  
Alcohol Intoxication ◽  
Branched Chain Amino Acids ◽  
Nitrogen Utilization ◽  
Branched Chain

The effects of complex compositions, containing branched-chain amino acids (BCAA), taurine and tryptophan, on the pool of free amino acids in the liver of rats were studied under the conditions of subchronic alcohol intoxication (SHAI). It was established that SHAI led to the decreased levels of treonine, lysine, oxyproline, arginine, b-alanine, as well as the depletion of the pool of irreplaceable amino acids in the liver of rats. Administration of the composition of BCAA and taurine was found to normalize the ratio of replaceable irreplaceable amino acids, the ratio of glycogenic and ketogenic amino acids, to activate the reaction of nitrogen utilization, and to increase Fisher’s index. The effects of the composition, containing BCAA, taurine and tryptophan, were similar to those of amino acid composition that did not contain tryptophan.

EFFECTS OF SODIUM PHENYLPYRUVATE ON AMINO ACID FORMATION IN BRAIN

1965 ◽  
Vol 43 (7) ◽  
pp. 835-840 ◽  
Author(s):  
T. Itoh
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Brain Cortex ◽  
Acid Formation ◽  
Potassium Ions ◽  
Inhibitory Effects ◽  
High Potassium ◽  
Brain Cortex Slices ◽  
Cortex Slices ◽  
Intracellular Labelling

Rat brain cortex slices were incubated with glucose-U-C14 in normal Krebs–Ringer phosphate media and also media 105 mM in potassium ions. Intracellular labelling of amino acids, such as glutamic acid, glutamine, γ-aminobutyric acid, aspartic acid, and alanine, was estimated by radioautography according to the method of Kini and Quastel. The respiration of brain cortex slices was little affected by the presence of phenylpyruvate. However, the formation of these amino acids was strongly suppressed. Moreover, in high-potassium media, the inhibitory effects of phenylpyruvate were greatly magnified. The addition of phenylalanine had no significant effect either on the oxygen consumption or on the amino acid formation when brain cortex slices were incubated with glucose-U-C14.

Effects of acetylcholine on potassium-induced changes of some amino acid uptakes and release in cerebral cortex slices from the rat

1977 ◽  
Vol 55 (3) ◽  
pp. 347-355 ◽  
Author(s):  
A. M. Benjamin ◽  
J. H. Quastel
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rat Brain ◽  
Brain Cortex ◽  
Potassium Ions ◽  
Acid Uptake ◽  
Rat Brain Cortex ◽  
Brain Cortex Slices ◽  
High Concentrations ◽  
Cortex Slices

High concentrations (105 μequiv./ml) of potassium ions in the incubation medium bring about reduced uptakes of L-glutamate, L-aspartate, and glycine but not of L-glutamine into rat brain cortex slices incubated aerobically in a physiological saline – glucose medium. The reductions are suppressed by acetylcholine (20 μM – 2 mM) in presence of eserine (0.1 mM) and not by tetrodotoxin (3 μM). The effect of acetylcholine is calcium dependent. It is diminished by atropine but not by d-tubocurarine (1 mM). Protoveratrine (5 μM) inhibition of amino acid uptake is not affected by acetylcholine but it is suppressed by tetrodotoxin. Acetylcholine and tetrodotoxin act independently of each other. Acetylcholine suppresses the potassium-evoked release of endogenous glutamate, aspartate, or glycine from incubated rat brain cortex slices. Its action on release is calcium dependent. Acetylcholine also suppresses the potassium-induced release of amino acids from rat brain cortex slices that have been previously incubated with 2 mM sodium L-glutamate or 2 mM sodium L-aspartate.It is suggested that increased cell concentrations of calcium ions, owing to high concentrations of potassium ions in the incubation medium, cause an increased glial permeability to sodium ions, with a resultant diminution of the sodium gradient. This diminution is considered to be responsible for the diminished concentrative uptake of L-glutamate, L-aspartate, or glycine, and the increased release of these amino acids. Acetylcholine suppresses the permeability change due to high concentrations of potassium ions and reverses the changed sodium gradient and the consequent change in amino acid uptake and release. It would seem that accumulation of acetylcholine in the intracellular spaces may affect glia, as well as neurons, modifying permeability to sodium ions and to various amino acids now assuming importance as possible transmitters.

Influence of exercise on free amino acid concentrations in rat tissues

1981 ◽  
Vol 50 (1) ◽  
pp. 41-44 ◽  
Author(s):  
G. L. Dohm ◽  
G. R. Beecher ◽  
R. Q. Warren ◽  
R. T. Williams
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino ◽  
Exercise Bout ◽  
Branched Chain Amino Acids ◽  
Rat Tissues ◽  
Acidic Amino Acids ◽  
Branched Chain ◽  
Amino Acid Contents ◽  
Amino Acid Concentrations

Levels of free amino acids in muscle, liver, and plasma were measured in rats that had either swum (1 or 2 h) or run (until exhausted). Exercise lowered alanine levels in all three tissues except for liver of exhausted rats. Exercise decreased the plasma levels of the acidic amino acids and their amides. Glutamate and glutamine levels were depressed in muscle, and the glutamine level was lowered in liver by exercise. Aspartate concentration was lowered by exercise in liver but elevated in muscle. The branched-chain amino acids were generally elevated by exercise as were tyrosine, phenylalanine, methionine, and lysine. Plasma 3-methylhistidine concentration was also elevated by an exercise bout. The changes observed in the amino acid contents of muscle, liver, and plasma are consistent with the increase in protein degradation during exercise that we previously reported. The lowered levels of some amino acids (e.g., alanine, glutamine, glutamate) seem to suggest that amino acid catabolism and/or gluconeogenesis is increased by exercise.

AMINO ACID TRANSPORT IN BRAIN CORTEX SLICES: II. COMPETITION BETWEEN AMINO ACIDS

1962 ◽  
Vol 40 (1) ◽  
pp. 1591-1602 ◽  
Author(s):  
P. N. Abadom ◽  
P. G. Scholefield
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rat Brain ◽  
Amino Acid Transport ◽  
Brain Cortex ◽  
Transport Systems ◽  
Acid Transport ◽  
Inhibitory Effects ◽  
Brain Cortex Slices ◽  
Cortex Slices

Evidence is presented which indicates that several amino acid transport systems are present in rat brain cortex slices, each with its own specificity with regard to substrate and with regard to amino acids which produce inhibitory effects. The nature of these inhibitory effects may be either direct (competition for a limiting number of sites) or indirect (as they are when glutamate or aspartate cause a decrease in the ATP content).Comparison of the specificities of the glycine transport systems present in rat brain cortex slices and in Ehrlich ascites carcinoma cells indicates that these two systems have little in common and the relation of this finding to the structural requirements necessary for chemotherapeutic activity is discussed.

THE EFFECTS OF LEAD AND TIN ORGANOMETALLIC COMPOUNDS ON THE METABOLISM OF RAT BRAIN CORTEX SLICES

1961 ◽  
Vol 39 (12) ◽  
pp. 1811-1827 ◽  
Author(s):  
A. Vardanis ◽  
J. H. Quastel
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rat Brain ◽  
Brain Slice ◽  
Brain Cortex ◽  
Brain Slices ◽  
Tetraethyl Lead ◽  
Rat Brain Cortex ◽  
Brain Cortex Slices ◽  
Cortex Slices

The effects of tetraethyl lead, tetraethyl tin, triethyl lead, and triethyl tin on the metabolism of rat brain cortex slices have been studied. Tetraethyl lead and tetraethyl tin inhibit the active transport of amino acids into rat brain cortex slices at concentrations and under conditions that show no effect on the glucose metabolism of the slices. Tetraethyl lead and tetraethyl tin inhibit the oxidation of L-glutamate by rat brain slices. This effect can be accounted for on the basis of the inhibitory action of these two substances on the transport of the amino acid into the brain tissue.Tetraethyl lead and tetraethyl tin abolish, at low concentrations, potassium-stimulated brain slice respiration in presence of glucose, having little or no effect on unstimulated brain slice respiration. However, the respiration of rat brain cortex slices previously treated with phospholipase A is highly sensitive to tetraethyl lead.The inhibitory effects of the two tetraethyl compounds show differences from those of their triethyl derivatives indicating that the effects of the former substances are not due to admixture with, or conversion to, the latter substances.The brain slices of rats poisoned with either tetraethyl lead or tetraethyl tin are unable to effect the active transport of amino acids. The appearance of this biochemical abnormality coincides with the manifestation of neuropathological symptoms.The mode of action of tetraethyl lead and of tetraethyl tin on brain metabolism in vitro is discussed. It is suggested that they may act on phospholipid groups concerned with amino acid and cation transport at the cell membrane.

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