scholarly journals Effect of ionic media on the intestinal transport of amino acids in rats in vitro

1972 ◽  
Vol 128 (1) ◽  
pp. 61P-61P
Author(s):  
A Mahmood ◽  
D P Sharma
Keyword(s):  
Amino Acids ◽  
Intestinal Transport ◽  
Ionic Media

Intestinal transport of amino acids studied in vitro with l-[131I]monoiodotyrosine

1960 ◽  
Vol 41 (2) ◽  
pp. 271-282 ◽  
Author(s):  
Daniel Nathans ◽  
Donald F. Tapley ◽  
Joan E. Ross
Keyword(s):  
Amino Acids ◽  
Intestinal Transport

Amino group requirement for in vitro intestinal transport of amino acids

1962 ◽  
Vol 202 (1) ◽  
pp. 171-173 ◽  
Author(s):  
Richard P. Spencer ◽  
Ted M. Bow ◽  
Mary Anne Markulis
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Cinnamic Acid ◽  
Concentration Gradient ◽  
Anthranilic Acid ◽  
Intestinal Transport ◽  
Amino Group ◽  
Phenylpyruvic Acid ◽  
Phenyllactic Acid

The amino group requirement for transintestinal transport of amino acids against a concentration gradient was investigated using hamster everted intestinal sacs. Although glycine (5 x 10–3 m) was transported against a concentration gradient, acetic acid was not. Similarly, l-phenylalanine was transported, whereas phenylpyruvic acid, phenylpropionic acid, phenyllactic acid, and cinnamic acid were not. l-Tryptophan was transported, but indolyllactic acid was not. The amino group was thus essential for transport by this system. n-Methylglycine and l-proline were accumulated from mucosa to serosa against a concentration gradient. Hence, one hydrogen of the amino group can be replaced. However, n-phenylglycine was not accumulated across these preparations, suggesting that the moiety replacing the amino hydrogen can not be sterically bulky. α-l-Alanine was transported against a concentration gradient from mucosa to serosa, but ß-alanine was not. This is in contrast to other systems which accumulate ß-alanine against a concentration gradient. Anthranilic acid, with the amino group in a relative ß position, was also not accumulated across everted intestinal sacs.

Chloride-dependent intestinal transport of imino and beta-amino acids in the guinea pig and rat

1994 ◽  
Vol 266 (3) ◽  
pp. R997-R1007 ◽  
Author(s):  
L. K. Munck ◽  
B. G. Munck
Keyword(s):  
Amino Acids ◽  
Small Intestine ◽  
Guinea Pig ◽  
Intestinal Transport ◽  
Isobutyric Acid ◽  
Acid Activation ◽  
Beta Alanine ◽  
Imino Acid ◽  
Proximal Small Intestine

The present study extends the observations of chloride-dependent intestinal amino acid carriers to the guinea pig and the rat using the technique of in vitro influx across the brush-border membrane of intact epithelium. Transport rates of D-glucose and L-amino acids are lowest in guinea pig proximal small intestine and are constant from midjejunum through distal ileum, except for leucine. The guinea pig possesses a sodium- and chloride-dependent, high-affinity, very low-capacity carrier of beta-amino acids for which taurine and beta-alanine compete and for which the Na(+)-taurine activation stoichiometry is 2.1 +/- 0.3:1. The imino acid carrier of the guinea pig is also chloride dependent with a Na(+)-Cl(-)-2-methylamino-isobutyric acid activation stoichiometry of 1.8 +/- 0.1:0.7 +/- 0.3:1. In contrast, the rat imino acid carrier is chloride independent and transport rates vary insignificantly along the small intestine. The rat taurine carrier has its maximal transport rate in midjejunum. It is chloride dependent but does not transport beta-alanine.

Intestinal transport of tryptophan and its analogs

1975 ◽  
Vol 228 (2) ◽  
pp. 496-500 ◽  
Author(s):  
TR Bosin ◽  
DR Hathaway ◽  
RP Maickel
Keyword(s):  
Amino Acids ◽  
Comparative Study ◽  
Active Transport ◽  
Intestinal Transport ◽  
Barrier Properties ◽  
Tetraethylammonium Bromide ◽  
Tryptophan Transport

A comparative study of the intestinal transport of DL-tryptophan and its 1-methylindole (tryptophan-l-Me) and benzo[b]thiophene (tryptophan-S) analogs has been carried out in vitro, using the everted intestinal sac of the rat and hamster. Both tryptophan and tryptophan-S are actively transported across the intestine, while tryptophan-l-Me is not actively transported. The active transport of tryptophan is competitively inhibited by tryptophan-S, suggesting a similar carrier, while tryptophan-l-Me is not an inhibitor of tryptophan transport, suggesting little or no interaction with the carrier. The transport of tryptophan and tryptophan-S is depressed at concentrations (10 mM), and all three amino acids produce subtle alterations in the barrier properties of the sacs, as evidenced by increased tetraethylammonium bromide-14C diffusion.

scholarly journals Studies on a wide-spectrum intestinal dipeptide uptake system in the monkey and in the human

1975 ◽  
Vol 146 (1) ◽  
pp. 133-139 ◽  
Author(s):  
M Das ◽  
A N Radhakrishnan
Keyword(s):  
Amino Acids ◽  
Wide Spectrum ◽  
Intestinal Transport ◽  
Uptake System ◽  
Efflux Rate ◽  
Leucine Uptake ◽  
Dipeptide Uptake ◽  
In Vitro Uptake ◽  
Broad Specificity

1. The intestinal transport of glycine and leucine residues of glycyl-L-leucine was studied in the monkey and in the human in vitro. Uptake of both [14C]glycyl-L-leuine and glycyl-L-[14C]leucine show similar Kt values, but there is a marked difference in the Vmax. values. Preliminary studies suggest that this anomalous difference in the Vmax. values may be due to the greater efflux rate of glycine from the tissue. 2. Arrhenius plots of both [14C]glycyl-L-leucine uptake and glycyl-L-[14C]leucine uptake in the monkey intestine show a discontinuity at about 20 degrees C. The activation energies above and below the discontinuity are similar for both [14C]glycyl-L-leucine uptake and glycyl-L-[14C]leucine uptake. These similarities in uptake characteristics suggest that the dipeptide glycyl-L-leucine is transported as one unit. 3. In the monkey intestine, glycyl-L-leucine uptake is inhibited by a wide variety of dipeptides, including those containing acidic and basic amino acids. The inhibition was shown to be competitive by using four representative dipeptides namely: L-alanyl-L-alanine, L-alanyl-L-leucine, L-glutamyl-L-glutamic acid and L-lysyl-L-lysine. The results strongly suggest that in the monkey intestine there may be a dipeptide-uptake system with an extremely broad specificity. These results were also confirmed in the human in a limited way.

Intestinal transport of l-tryptophan in vitro: inhibition by high concentrations

1960 ◽  
Vol 199 (6) ◽  
pp. 1033-1036 ◽  
Author(s):  
Richard P. Spencer ◽  
A. H. Samiy
Keyword(s):  
Amino Acids ◽  
Small Intestine ◽  
Aromatic Amino Acids ◽  
Intestinal Transport ◽  
Serosal Side ◽  
Mutual Inhibition ◽  
High Concentrations ◽  
Two Sides ◽  
Bathing Fluid

At a concentration of 5 x 10–3 m, everted hamster intestinal sacs showed net transport of l-tryptophan from the mucosal to the serosal side, when the concentration was initially equal on the two sides. Thus, l-tryptophan is not an exception to the generalization that such intestinal preparations transport monoamino-monocarboxylic amino acids against a concentration gradient. High concentrations of l-tryptophan inhibit such transport. This may account for previous failure by others to observe l-tryptophan transport against a gradient at an initial concentration of 20 x 10–3 m. Transport of l-tryptophan was greater by sacs from the middle of the small intestine than by those from the ends (this has been previously reported for l-phenylalanine and l-tyrosine). On the basis of this observation and those of mutual inhibition of transport, it is likely that the four aromatic amino acids share at least one common step in their intestinal absorption. Segments of hamster small intestine have been shown to accumulate l-tryptophan, developing a concentration greater than that of the bathing fluid.

Polycations. A new class of inhibitors for in vitro small intestinal transport of sugars and amino acids in the rat

1983 ◽  
Vol 727 (1) ◽  
pp. 135-143 ◽  
Author(s):  
Bernd Elsenhans ◽  
Roland Blume ◽  
Bernhard Lembcke ◽  
Wolfgang F. Caspary
Keyword(s):  
Amino Acids ◽  
Intestinal Transport ◽  
New Class ◽  
Small Intestinal

Antimyotoxic Activity of Synthetic Peptides Derived from Bothrops atrox Snake Gamma Phospholipase A2 Inhibitor Selected by Virtual Screening

2019 ◽  
Vol 19 (22) ◽  
pp. 1952-1961 ◽  
Author(s):  
J.C. Sobrinho ◽  
A.F. Francisco ◽  
R. Simões-Silva ◽  
A.M. Kayano ◽  
J.J. Alfonso Ruiz Diaz ◽  
...  
Keyword(s):  
Amino Acids ◽  
Molecular Docking ◽  
Synthetic Peptides ◽  
Cell Damage ◽  
Neutralization Assay ◽  
Phospholipase Activity ◽  
Phospholipases A2 ◽  
Catalytically Active ◽  
Bothrops Atrox

Background: Several studies have aimed to identify molecules that inhibit the toxic actions of snake venom phospholipases A2 (PLA2s). Studies carried out with PLA2 inhibitors (PLIs) have been shown to be efficient in this assignment. Objective: This work aimed to analyze the interaction of peptides derived from Bothrops atrox PLIγ (atPLIγ) with a PLA2 and to evaluate the ability of these peptides to reduce phospholipase and myotoxic activities. Methods: Peptides were subjected to molecular docking with a homologous Lys49 PLA2 from B. atrox venom modeled by homology. Phospholipase activity neutralization assay was performed with BthTX-II and different ratios of the peptides. A catalytically active and an inactive PLA2 were purified from the B. atrox venom and used together in the in vitro myotoxic activity neutralization experiments with the peptides. Results: The peptides interacted with amino acids near the PLA2 hydrophobic channel and the loop that would be bound to calcium in Asp49 PLA2. They were able to reduce phospholipase activity and peptides DFCHNV and ATHEE reached the highest reduction levels, being these two peptides the best that also interacted in the in silico experiments. The peptides reduced the myotubes cell damage with a highlight for the DFCHNV peptide, which reduced by about 65%. It has been suggested that myotoxic activity reduction is related to the sites occupied in the PLA2 structure, which could corroborate the results observed in molecular docking. Conclusion: This study should contribute to the investigation of the potential of PLIs to inhibit the toxic effects of PLA2s.

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