Effects of Phenylalanine Analogues on Renal Tubular Reabsorption of Amino Acids in the Rat

1977 ◽  
Vol 53 (4) ◽  
pp. 355-364
Author(s):  
C. W. I. Owens
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plasma Concentrations ◽  
Tubular Reabsorption ◽  
Urinary Flow ◽  
Serial Determination ◽  
Forced Diuresis ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular

1. A method is described for the serial determination of renal tubular reabsorption of amino acids in the ethanol-anaesthetized rat. It utilizes intravenous radio-labelled inulins, automated amino acid analysis and forced diuresis. 2. Intravenous loading with phenylalanine and infusion of phenylalanine analogues in this preparation decrease reabsorption of endogenous amino acids in accordance with existing concepts of amino acid transport. 3. Maximal tubular reabsorption (Tmax.) could not be demonstrated for phenylalanine at plasma concentrations below 9 mmol/l. 4. Infusion of phenylalanine analogues into phenylalanine-loaded (‘phenylketonuric’) rats did not specifically inhibit tubular reabsorption of phenylalanine and it is unlikely that any of the substances tested have a potential therapeutic use in man. 5. p-Guanidino derivatives of phenylalanine, in contrast to p-amino derivatives, appear to cause a dose-related basic aminoaciduria. 6. Consideration of urinary flow rates and sodium excretion suggests that the ethanol anaesthesia does not modify amino acid reabsorption through effects on sodium transport or antidiuretic hormone.

Interactions of neutral and acidic amino acids in renal tubular transport

1962 ◽  
Vol 202 (3) ◽  
pp. 577-583 ◽  
Author(s):  
William A. Webber
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plasma Concentrations ◽  
Side Chain ◽  
Neutral Amino Acids ◽  
Acidic Amino Acids ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular Transport ◽  
Renal Tubular ◽  
Amino Acid Concentrations

The effects of intravenous infusions of a variety of neutral and acidic amino acids on the plasma concentrations and excretions of naturally occurring amino acids were studied in dogs. Conventional clearance techniques were used, and the amino acid concentrations were determined by ion exchange column chromatography. Infusion of either l-glutamic acid or l-aspartic acid caused a gross increase in the plasma concentration and excretion of the other. Infusions of neutral amino acids including glycine, l-alanine, l-leucine, l-methionine, l-proline, and l-phenylalanine caused some minor changes in the endogenous plasma amino acid concentrations. They produced increases in the excretion of other neutral amino acids and, in some cases, of acidic and basic amino acids as well. In general, amino acids with long side chains were most effective in inhibiting reabsorption while cyclic side-chain compounds were less effective. There appear to be at least three somewhat separable mechanisms for renal tubular reabsorption of amino acids in dogs.

Effect of Various Amino Acids on the Renal Tubular Reabsorption of Inorganic Sulfate in the Dog

1956 ◽  
Vol 185 (3) ◽  
pp. 539-542 ◽  
Author(s):  
Fredrik Berglund ◽  
William D. Lotspeich
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Tubular Reabsorption ◽  
Acid Inhibition ◽  
Maximal Rate ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular ◽  
Inorganic Sulfate

Various amino acids depress the sulfate-Tm in the dog. The effects of l-alanine, glycine, d-alanine and l-arginine are compared. The capacity of any one of these amino acids to depress sulfate-Tm correlates directly with maximal rate of reabsorption of the amino acid. The nature of the amino acid inhibition, its relation to amino acid reabsorption, the amino-acidurias and some general problems of renal tubular reabsorption are discussed.

Application of FT-IR Spectrometry to Determine the Global Metabolic Adaptations to Physical Conditioning in Sportsmen

2002 ◽  
Vol 56 (10) ◽  
pp. 1259-1267 ◽  
Author(s):  
Cyril Petibois ◽  
Georges Cazorla ◽  
André Cassaigne ◽  
Gérard Déléris
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ir Spectra ◽  
Plasma Concentrations ◽  
Physical Conditioning ◽  
Ir Spectrometry ◽  
Metabolic Adaptations ◽  
Spectral Area ◽  
Ft Ir

Global metabolic adaptations to physical conditioning were described in 15 subjects by FT-IR spectrometry as the method allowed determination of glucose (Glc), lactate (La), glycerol, triglycerides (TG), fatty acyl moieties (FAM), and total amino acids plasma concentrations. Subtraction of plasma FT-IR spectra obtained at resting state from the exercise spectra also allowed determination of the biomolecular response to exercise. On week 1, exercise induced a transient hypoglycemia, a lactatemia increase of 153%, a FAM depletion of 27%, and a TG concentration decrease of 28%. Protein contents increased by 2%, but these were partly catabolized for amino acid supply (+27%), suggesting an important metabolic stress during exercise. On week 3, exercise hypoglycemia had disappeared, lactate increase was diminished by 91%, TG contents were decreased by 14%, and proteins and amino acids exhibited higher absorption increases. On week 5, TG and FAM concentrations were markedly increased during exercise, protein absorption was still increased (+9%), but amino acid blood release was diminished by 81%. These results described positive adaptations to training. Furthermore, FAM concentration could be determined from plasma FT-IR spectra by using the 2996–2819 cm−1 spectral area [ νas(CH3), νas(CH2), νs(CH3), and νs(CH2) absorbance; 0.82 mMol·L−1, a.u. cm−1], as well as for amino acid concentration by using the ν(COO−) spectral area (1430–1360 cm−1; 0.062 g·L−1, a.u. × cm−1). FT-IR spectrometry was useful to determine simultaneously various plasma concentrations and most of the biomolecular changes through successive samples.

Effect of parathyroid hormone on renal tubular reabsorption of amino acids

Metabolism ◽  
1974 ◽  
Vol 23 (8) ◽  
pp. 715-727 ◽  
Author(s):  
Elizabeth M. Short ◽  
Louis J. Elsas ◽  
Leon E. Rosenberg
Keyword(s):  
Amino Acids ◽  
Parathyroid Hormone ◽  
Tubular Reabsorption ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular

CHARACTERISTICS OF ACIDIC AMINO ACID TRANSPORT IN MAMMALIAN KIDNEY

1963 ◽  
Vol 41 (1) ◽  
pp. 131-137 ◽  
Author(s):  
William A. Webber
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Tubular Reabsorption ◽  
Side Chain ◽  
Acid Transport ◽  
Acidic Amino Acid ◽  
Neutral Amino Acids ◽  
Wide Range ◽  
Renal Tubular

A series of clearance experiments on dogs were carried out which were designed to confirm and characterize the renal tubular reabsorption of glutamic and aspartic acids. Tubular reabsorption was measured and found to reach a maximum of about 100 μmole/minute for L-glutamic and L-aspartic acids and a slightly lower level for D-aspartic. Competitive studies using substituted amino acids were performed and three patterns of inhibition of amino acid reabsorption observed. Acidic amino acids inhibited the reabsorption of each other, while neutral amino acids (and an acidic amino acid substituted so as to have a neutral side chain) inhibited the reabsorption of a wide range of other amino acids. Compounds with the amino group or either carboxyl group substituted or absent, but not resembling neutral amino acids, were not inhibitory. There appears to be a specialized mechanism for acidic amino acid transport which probably requires all three functional groups but which may be interfered with by a compound with alpha carboxyl and amino groups and a neutral side chain.

INHIBITORY EFFECT OF CERTAIN AMINO ACIDS ON RENAL TUBULAR ABSORPTION OF PHOSPHATE

1967 ◽  
Vol 45 (1) ◽  
pp. 103-114 ◽  
Author(s):  
Alfred F. Michael ◽  
Keith N. Drummond
Keyword(s):  
Amino Acids ◽  
Parathyroid Hormone ◽  
Inhibitory Effect ◽  
Tubular Reabsorption ◽  
Hormone Action ◽  
Basic Amino Acids ◽  
Phosphate Excretion ◽  
Renal Tubular Reabsorption ◽  
Tubular Absorption ◽  
Renal Tubular

Infusion of certain neutral L-amino acids (alanine, glycine, valine, and tryptophan) into dogs resulted in an inhibition of the renal tubular reabsorption of phosphate and increased phosphate excretion. This was seen in both the parathyroidectomized animal and under conditions of exogenous parathormone infusion, indicating that the phosphaturia induced by amino acids is independent of parathyroid hormone action. This effect was stereospecific and did not occur with D-alanine; no effect was observed after infusion of the basic amino acids L-arginine and L-lysine.

CHARACTERISTICS OF ACIDIC AMINO ACID TRANSPORT IN MAMMALIAN KIDNEY

1963 ◽  
Vol 41 (1) ◽  
pp. 131-137 ◽  
Author(s):  
William A. Webber
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Tubular Reabsorption ◽  
Side Chain ◽  
Acid Transport ◽  
Acidic Amino Acid ◽  
Neutral Amino Acids ◽  
Wide Range ◽  
Renal Tubular

A series of clearance experiments on dogs were carried out which were designed to confirm and characterize the renal tubular reabsorption of glutamic and aspartic acids. Tubular reabsorption was measured and found to reach a maximum of about 100 μmole/minute for L-glutamic and L-aspartic acids and a slightly lower level for D-aspartic. Competitive studies using substituted amino acids were performed and three patterns of inhibition of amino acid reabsorption observed. Acidic amino acids inhibited the reabsorption of each other, while neutral amino acids (and an acidic amino acid substituted so as to have a neutral side chain) inhibited the reabsorption of a wide range of other amino acids. Compounds with the amino group or either carboxyl group substituted or absent, but not resembling neutral amino acids, were not inhibitory. There appears to be a specialized mechanism for acidic amino acid transport which probably requires all three functional groups but which may be interfered with by a compound with alpha carboxyl and amino groups and a neutral side chain.

scholarly journals Renal Disposition of Amylase, Lipase, and Lysozyme in the Dog

1988 ◽  
Vol 25 (6) ◽  
pp. 443-449 ◽  
Author(s):  
R. M. Jacobs
Keyword(s):  
Amylase Activity ◽  
Tubular Reabsorption ◽  
Urinary Amylase ◽  
Forced Diuresis ◽  
Fractional Clearance ◽  
Renal Tubular Reabsorption ◽  
Urinary Inhibitors ◽  
Baseline Values ◽  
Renal Tubular ◽  
Arteriovenous Difference

Normal adult dogs were given intravenously lysine hydrochloride to abolish renal tubular reabsorption. The treatment caused tubular proteinuria. Once forced diuresis was established, fractional clearances for amylase, lipase, and lysozyme increased five-, 18-, and 857-fold over the baseline values, respectively. There was relatively little tubular reabsorption of amylase, and urinary amylase activity remained low. A renal arteriovenous difference in amylase activity was not present. Urinary amylase activity could not be reactivated by the addition of serum or treatment with dithiothreitol. Urinary inhibitors of amylase activity were not detected. Immunoreactive urinary amylase did not exceed kinetically measured urinary amylase. Therefore, the presence of irreversibly inactivated amylase did not explain the low fractional clearance of amylase. A small amount of serum macroamylase was present, but macroamylasemia did not account for canine amylase failing to pass the glomerular filter. It appears that the renal loss of amylase in the dog is not an important excretory route.

Lysine Infusion in Cystinuria: Theoretical Renal Thresholds for Lysine

1973 ◽  
Vol 44 (2) ◽  
pp. 99-111 ◽  
Author(s):  
Frances T. Lester ◽  
D. C. Cusworth
Keyword(s):  
Amino Acids ◽  
Intravenous Infusion ◽  
Tubular Reabsorption ◽  
Water Diuresis ◽  
Renal Handling ◽  
The Third ◽  
Lysine Concentration ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular ◽  
Normal Adults

1. The renal handling of lysine was studied during the intravenous infusion of a lysine load given in such a way that the plasma lysine concentration was constantly increasing. Theoretical renal thresholds, and maximum rates of renal tubular reabsorption of lysine, have been determined in three normal adults, five homozygous cystinuric patients, and three persons, two ‘completely’ and the third ‘incompletely’ recessive, heterozygotes for cystinuria. All the cystinuric patients were found to have thresholds at less than 1 mg of lysine/100 ml of plasma; the thresholds of all three heterozygotes fell within the same range as those of the three normal persons, that is, at values only two to three times the fasting plasma lysine concentration. 2. Not only was the lysine load shown to greatly increase the excretion of cystine, arginine and ornithine in the normal and heterozygous persons, but it was also shown to increase the already high clearance of these three amino acids in three of the homozygous cystinuric patients. 3. It was shown that a water diuresis alone will not cause increased excretion of any amino acids except taurine.

scholarly journals Progress towards reduced-crude protein diets for broiler chickens and sustainable chicken-meat production

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sonia Yun Liu ◽  
Shemil P. Macelline ◽  
Peter V. Chrystal ◽  
Peter H. Selle
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Broiler Chickens ◽  
Crude Protein ◽  
Plasma Concentrations ◽  
Essential Amino Acids ◽  
Chicken Meat ◽  
Meat Production ◽  
Accurate Identification ◽  
Reduced Crude Protein

AbstractThe prime purpose of this review is to explore the pathways whereby progress towards reduced-crude protein (CP) diets and sustainable chicken-meat production may be best achieved. Reduced-CP broiler diets have the potential to attenuate environmental pollution from nitrogen and ammonia emissions; moreover, they have the capacity to diminish the global chicken-meat industry’s dependence on soybean meal to tangible extents. The variable impacts of reduced-CP broiler diets on apparent amino acid digestibility coefficients are addressed. The more accurate identification of amino acid requirements for broiler chickens offered reduced-CP diets is essential as this would diminish amino acid imbalances and the deamination of surplus amino acids. Deamination of amino acids increases the synthesis and excretion of uric acid for which there is a requirement for glycine, this emphasises the value of so-called “non-essential” amino acids. Starch digestive dynamics and their possible impact of glucose on pancreatic secretions of insulin are discussed, although the functions of insulin in avian species require clarification. Maize is probably a superior feed grain to wheat as the basis of reduced-CP diets; if so, the identification of the underlying reasons for this difference should be instructive. Moderating increases in starch concentrations and condensing dietary starch:protein ratios in reduced-CP diets may prove to be advantageous as expanding ratios appear to be aligned to inferior broiler performance. Threonine is specifically examined because elevated free threonine plasma concentrations in birds offered reduced-CP diets may be indicative of compromised performance. If progress in these directions can be realised, then the prospects of reduced-CP diets contributing to sustainable chicken-meat production are promising.

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