Kinetics of Uptake of An Amino Acid and a Dipeptide into Hamster Jejunum and Ileum: The Effect of Semistarvation and Starvation

1979 ◽  
Vol 56 (5) ◽  
pp. 487-492 ◽  
Author(s):  
H. P. Schedl ◽  
D. Burston ◽  
Elizabeth Taylor ◽  
D. M. Matthews
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Unit Length ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Intestinal Uptake ◽  
Main Effect ◽  
Kinetics Of Uptake ◽  
Kinetics Of

1. This paper reports an investigation of the effects of semistarvation and starvation on the kinetics of uptake of an amino acid, l-leucine, and a hydrolysis-resistant dipeptide, Gly-Sar, by rings of everted hamster jejunum and ileum in vitro. The concentration range used was 0·1–100 mmol/l. Total uptake, non-mediated uptake and Kt and Vmax. for mediated influx were estimated. 2. At many concentrations, both semistarvation and starvation caused a decrease in uptake of the peptide and the amino acid. Uptake of the peptide was more severely depressed than that of the amino acid. In control animals, the jejunum was the site of maximal uptake of Gly-Sar, and the ileum the site of maximal uptake of leucine. In semistarved and starved animals, the ileum became the site of maximal uptake of Gly-Sar, as it was for leucine. The effects of semistarvation and starvation on uptake were similar whether this was expressed per unit wt. or per unit length, though they were accentuated when expressed per unit length, since the intestine lost weight per unit length. 3. The main effect of semistarvation and starvation on the kinetics of mediated influx of the amino acid and the peptide was to reduce Vmax. in both jejunum and ileum. This effect was compatible with a reduction in the number of mediated transport sites for both the amino acid and the peptide. The observation that mediated influx of the peptide was more severely affected than that of the amino acid supports the hypothesis of the independence of the mechanisms for intestinal uptake of peptides and amino acids.

scholarly journals Action of growth hormone in vitro on the net uptake and incorporation into protein of amino acids in muscle from intact rabbits given protein-deficient diets

1976 ◽  
Vol 35 (1) ◽  
pp. 1-10 ◽  
Author(s):  
M. R. Turner ◽  
P. J. Reeds ◽  
K. A. Munday
Keyword(s):  
Amino Acids ◽  
Growth Hormone ◽  
Protein Synthesis ◽  
Amino Acid ◽  
De Novo ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Amino Acid Incorporation ◽  
Acid Incorporation

1. Net amino acid uptake, and incorporation into protein have been measured in vitro in the presence and absence of porcine growth hormone (GH) in muscle from intact rabbits fed for 5 d on low-protein (LP), protein-free (PF) or control diets.2. In muscle from control and LP animals GH had no effect on the net amino acid uptake but stimulated amino acid incorporation into protein, although this response was less in LP animals than in control animals.3. In muscle from PF animals, GH stimulated both amino acid incorporation into protein and the net amino acid uptake, a type of response which also occurs in hypophysectomized animals. The magnitude of the effect of GH on the incorporation of amino acids into protein was reduced in muscle from PF animals.4. The effect of GH on the net amino acid uptake in PF animals was completely blocked by cycloheximide; the uptake effect of GH in these animals was dependent therefore on de novo protein synthesis.5. It is proposed that in the adult the role of growth hormone in protein metabolism is to sustain cellular protein synthesis when there is a decrease in the level of substrate amino acids, similar to that which occurs during a short-term fast or when the dietary protein intake is inadequate.

scholarly journals Dicarboxylic Amino Acid Uptake in Normal, Friedreich's Ataxia, and Dicarboxylic Aminoaciduria Fibroblasts

1979 ◽  
Vol 6 (2) ◽  
pp. 263-273 ◽  
Author(s):  
S.B. Melancon ◽  
B. Grenier ◽  
L. Dallaire ◽  
M. Potier ◽  
G. Fontaine ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Uptake ◽  
Friedreich’S Ataxia ◽  
Friedreich's Ataxia ◽  
Acid Uptake ◽  
Normal Cells ◽  
Dicarboxylic Amino Acid ◽  
Normal Individuals ◽  
Kinetics Of

SummaryGlutamic and aspartic acid uptake was measured in skin fibroblasts from patients with Friedreich's Ataxia, dicarboxylic aminoaciduria, and normal individuals. The results showed no difference in uptake kinetics of either dicarboxylic amino acids between Friedreich's Ataxia and normal cells, but reduced uptake velocities in dicarboxylic aminoaciduria fibroblasts. Friedreich's Ataxia fibroblasts were, however, less calcium-dependant and more magnesium and phosphate-dependent than controls in glucose-free incubation mixture. This difference might be related to some degree of glucose intolerance by Friedreich's Ataxia fibroblasts in culture.

Influence of organic cations on basic amino-acid uptake by human placental villi

1995 ◽  
Vol 7 (6) ◽  
pp. 1491
Author(s):  
RB Krishna ◽  
J Dancis ◽  
M Levitz
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Basic Amino Acid ◽  
Amino Acid Uptake ◽  
Progressive Increase ◽  
Amino Acid Transporters ◽  
Acid Uptake ◽  
Chorionic Villi ◽  
Basic Amino Acids ◽  
Kinetics Of

Human placental chorionic villi were incubated for 30 min with [3H]lysine or [3H]arginine and the distribution ratios (intracellular:extracellular concentrations) were determined. The ratios remained unchanged when Na+ in Earle's buffered salt solution was replaced with Li+. When Na+ was replaced with choline there was a significant increase is distribution ratios (lysine 1.34 +/- 0.33 v. 3.99 +/- 0.15, arginine 1.95 +/- 0.37 v. 5.05 +/- 1.16). Leucine, a neutral amino acid with a Na(+)-independent transport system, was unaffected by choline substitution. The distribution ratio for alanine, which is Na(+)-dependent, was reduced (2.50 +/- 0.41 v. 1.45 +/- 0.20). Two other quarternary amines, acetyl-beta-methylcholine and tetraethylammonium chloride (TEA) caused similar increases in the distribution ratios of the basic amino acids. Hordenine, a tertiary amine, was less effective and there was little or no effect with ephedrine, a secondary amine. The choline effect was first observable at concentrations of 105 mM. With TEA, there was a progressive increase in distribution ratios beginning at 29 mM. Lysine efflux was measured after incubation of villi with lysine in Earle's buffer or choline buffer. Lysine was rapidly released to the fresh medium with 25% more retained in choline-exposed villi. The amines may cause alterations in the kinetics of basic amino-acid transporters or may modify other aspects of placental physiology permitting an increase retention of the basic amino acids.

Gamma-Glutamyl-Amino Acids as Signals for the Hormonal Regulation of Amino Acid Uptake by the Mammary Gland of the Lactating Rat

Neonatology ◽  
1985 ◽  
Vol 48 (4) ◽  
pp. 250-256 ◽  
Author(s):  
Juan R. Viña ◽  
Inmaculada R. Puertes ◽  
Juan B. Montoro ◽  
Guillermo T. Saez ◽  
José Viña
Keyword(s):  
Amino Acids ◽  
Mammary Gland ◽  
Amino Acid ◽  
Hormonal Regulation ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Gamma Glutamyl

The mechanisms of amino acid uptake byBrugia pahangi in vitro

1983 ◽  
Vol 69 (2) ◽  
pp. 247-253 ◽  
Author(s):  
R. E. Howells ◽  
A. M. Mendis ◽  
P. G. Bray
Keyword(s):  
Amino Acid ◽  
Amino Acid Uptake ◽  
Acid Uptake

scholarly journals Identification in skeletal muscle of a distinct extracellular pool of amino acids, and its role in protein synthesis

1971 ◽  
Vol 121 (5) ◽  
pp. 817-827 ◽  
Author(s):  
R. C. Hider ◽  
E. B. Fern ◽  
D. R. London
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Incubation Medium ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Longus Muscle ◽  
Kinetics Of

1. The kinetics of radioactive labelling of extra- and intra-cellular amino acid pools and protein of the extensor digitorum longus muscle were studied after incubations with radioactive amino acids in vitro. 2. The results indicated that an extracellular pool could be defined, the contents of which were different from those of the incubation medium. 3. It was concluded that amino acids from the extracellular pool, as defined in this study, were incorporated directly into protein.

scholarly journals Studies in Amino-acid Uptake by RD3 Sarcoma Cell Suspensions In Vitro

1955 ◽  
Vol 9 (3) ◽  
pp. 480-485 ◽  
Author(s):  
G Wiseman ◽  
F N Ghadially
Keyword(s):  
Amino Acid ◽  
Amino Acid Uptake ◽  
Cell Suspensions ◽  
Acid Uptake ◽  
Sarcoma Cell

The uptake of amino acids by mouse cells (strain LS) during growth in batch culture and chemostat culture: the influence of cell growth rate

1967 ◽  
Vol 168 (1013) ◽  
pp. 421-438 ◽  
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Amino Acid ◽  
Cell Growth ◽  
Glutamic Acid ◽  
Batch Culture ◽  
Amino Acid Uptake ◽  
Essential Amino Acids ◽  
Growth Yields ◽  
Acid Uptake

The uptake of thirteen essential amino acids by mouse LS cells in suspension culture was determined by bacteriological assay methods. Chemostat continuous-flow cultures were used to determine the effect of different cell growth rates on the quantitative amino acid requirements for growth. The growth yields of the cells ( Y = g cell dry weight produced/g amino acid utilized) were calculated for each of the essential amino acids. A mixture of the non-essential amino acids, serine, alanine and glycine increased the cell yield from the essential amino acids. The growth yields from nearly all the essential amino acids in batch culture were increased when glutamic acid was substituted for the glutamine in the medium. The growth yields from the amino acids in batch culture were much less at the beginning than at the end of the culture. The highest efficiencies of conversion of amino acids to cell material were obtained by chemostat culture. When glutamic acid largely replaced the glutamine in the medium the conversion of amino acid nitrogen to cell nitrogen was 100 % efficient (that is, the theoretical yield was obtained) at the optimum growth rate (cell doubling time, 43 h). The maximum population density a given amino acid mixture will support can be calculated from the data. It is concluded that in several routinely used tissue culture media the cell growth is limited by the amino acid supply. In batch culture glutamine was wasted by (1) its spontaneous decomposition to pyrrolidone carboxylic acid and ammonia, and (2) its enzymic breakdown to glutamic acid and ammonia, but also glutamine was used less efficiently than glutamic acid. Study of the influence of cell growth rate on amino acid uptake rates per unit mass of cells indicated that a marked change in amino acid metabolism occurred at a specific growth rate of 0.4 day -1 (cell doubling time, 43 h). With decrease in specific growth rate below 0.4 day -1 there was a marked stimulation of amino acid uptake rate per cell and essential amino acids were consumed increasingly for functions other than synthesis of cell material.

scholarly journals Rationally Design of a Proline Transporter Inhibitor with Anti-Trypanosoma Cruzi Activity

2019 ◽  
Author(s):  
Lucia Fargnoli ◽  
Esteban A. Panozzo-Zénere ◽  
Lucas Pagura ◽  
María Julia Barisón ◽  
Julia A. Cricco ◽  
...  
Keyword(s):  
Amino Acid ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Variable Region ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Cell Infection ◽  
Atp Production ◽  
First Case

L-Proline is an important amino acid for the pathogenic protists belonging to <i>Trypanosoma</i> and <i>Leishmania </i>genera. In <i>Trypanosoma cruzi</i>, the etiological agent of Chagas disease, this amino acid is involved in fundamental biological processes such as ATP production, differentiation of the insect and intracellular stages, the host cell infection and the resistance to a variety of stresses, including nutritional and osmotic as well as oxidative imbalance. In this study, we explore the L-Proline uptake as a chemotherapeutic target for <i>T. cruzi</i>. For this, we propose a novel rational to design inhibitors containing this amino acid as a recognizable motif. This rational consists of conjugating the amino acid (proline in this case) to a linker and a variable region able to block the transporter. We obtained a series of sixteen 1,2,3-triazolyl-proline derivatives through alkylation and copper(I)-catalyzed azide-alkyne cycloaddition (click chemistry) for <i>in vitro</i> screening against <i>T. cruzi </i>epimastigotes, trypanocidal activity and proline uptake. We successfully obtained inhibitors that are able to interfere with the amino acid uptake, which validated the first example of a rationally designed chemotherapeutic agent targeting a metabolite's transport. Additionally, we designed and prepared fluorescent analogues of the inhibitors that were successfully taken up by <i>T. cruzi</i>, allowing following up their intracellular fate. In conclusion, we successfully designed and produced a series of metabolite uptake inhibitors. This is one of few examples of rationally designed amino acid transporter inhibitor, being the first case where the strategy is applied on the development of chemotherapy against Chagas disease. This unprecedented development is remarkable having in mind that only a small percent of the metabolite transporters has been studied at the structural and/or molecular level.

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