Comparative Aspects of Amino Acid Ttansport in Guinea Pig, Rabbit and Rat Small Intestine

Munck, B. G.

doi:10.1007/978-3-642-69109-6_20

Cited by 9 publications

(10 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These estimates indicate that one or more low-affinity transport systems contributes sig-/Leu nificantly to ~mc even in the presence of 100 mM lysine. If it is assumed that JCm~ by the low-affinity transport system for lysine is 4/zmol/cm 2 9 hr with a Kt of 34 mM and 4.8 by the carrier of MeAIB with a Kt of 25 mM (Munck, 1983), the total JLm~U calculated for 1 mM leucine will decrease from approximately 0.3/xmol/cm 2 9 hr at 1 mM leucine to 0.18/zmol/cm 2 9 hr under inhibition by 25 mM leucine. If the values of Fig.…”

Section: Lysine-resistant Transport Of Alanine and Leucinementioning

confidence: 99%

“…However, a following study (Munck, accompanying paper) of the transport of/3-alanine and 2-(methylamino)isobutyric acid indicates that in addition the rabbit ileum possesses an imino acid carrier, which is also a low-affinity carrier of neutral a.a., and a/3-alanine-accepting carrier, which is also a high-affinity carrier of both neutral and cationic a.a. Some of the results have been presented in a review of the comparative aspects of intestinal transport of amino acids (Munck, 1983).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Transport of neutral and cationic amino acids across the brush-border membrane of the rabbit ileum

Munck

1985

J. Membrain Biol.

Self Cite

View full text Add to dashboard Cite

The transport of sugars and amino acids across the brush-border membrane of the distal rabbit ileum has been studied. The kinetics of the transport of glucose demonstrated that the data obtained with the present technique are less distorted by unstirred layers than those obtained with the same technique adapted to the use of magnetic stirring. The role of depolarization of the electrical potential difference across the brush-border membrane in mutual inhibition between different classes of amino acids was estimated by measurements of the effects of high concentrations of alanine and lysine on the transport of galactose. It was found that this role would be insignificant in the present study. By measurements of the transport of alanine, leucine and lysine and the inhibitory interactions between these amino acids the function of three transport systems has been delineated. The transport of lysine is resolved in a high- and a low-affinity contribution. At 140 mM sodium these transport systems may also function as respectively high- and low-affinity contributors to the transport of neutral amino acids. At 0 mM sodium the high-affinity system remains a high-affinity system for cationic and neutral amino acids with reduced capacity especially for the neutral amino acids. At 0 mM sodium the low-affinity system's affinity for lysine is reduced and it is inaccessible to neutral amino acids. In addition to the two systems for lysine transport the existence of a lysine-resistant, sodium-dependent, high-affinity system for the transport of neutral amino acids has been confirmed. It seems unlikely that the distal ileum is equipped with a low-affinity, sodium-independent system for the transport of neutral amino acids.

show abstract

Section: Lysine-resistant Transport Of Alanine and Leucinementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transport of neutral and cationic amino acids across the brush-border membrane of the rabbit ileum

Munck

1985

J. Membrain Biol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Transport of imino acids and non-a-amino acids by mammalian small intestine has been described mostly by experiments on the rat small intestine, which appears to possess only one system for the transport of these two groups of amino acids (Munck, 1981). The guinea pig, it now appears (Munck, 1983), possesses one system for the transport of imino acids but seems not to transport nona-amino acids.…”

Section: Introductionmentioning

confidence: 97%

“…However, preliminary experiments (Munck, 1983) indicated that in the rabbit ileum at least two systems were involved in the transport of these amino acids. These transport systems have now been characterized; and, while these studies were completed, results obtained with microvesicles of the brush-border membrane from the total rabbit small intestine except the orally first and the anally last 30 cm have characterized a MeAIB transporting system (Stevens, Ross & Wright, 1982).…”

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

Transport of imino acids and non-α-amino acids across the brush-border membrane of the rabbit ileum

Munck

1985

J. Membrain Biol.

View full text Add to dashboard Cite

The transport of beta-alanine and MeAIB and their effects as inhibitors of the transport of alanine, leucine and lysine across the brush-border membrane of the intact epithelium from the rabbit's distal ileum has been examined. Two separate transport systems have been characterized: 1) A sodium-dependent, beta-alanine-accepting system, which is a high-affinity transport system for alpha-amino-monocarboxylic acids (neutral a.a.) and for cationic a.a., accepts non-alpha-amino acids as well as non-alpha-imino acids, is moderately stereospecific, and for which the affinity of a neutral a.a. is greatly reduced by N-methylation. 2) A sodium-dependent transport system for imino acids, which is inaccessible to cationic amino acids and non-alpha-amino acids but accepts cyclic, non-alpha-imino acids, is moderately stereospecific, and for which neutral a.a. have much lower affinities than their N-methylated derivatives. On the basis of the observations of this and the preceding paper five transport systems for amino acids are ascribed to the rabbit ileum. Some discrepancies between the present results and those obtained with brush-border membrane microvesicles from the rabbit small intestine are discussed.

show abstract

Influence of γ‐aminobutyric acid on baclofen intestinal absorption

Nácher¹,

Polache²,

Moll-Navarro³

et al. 1994

Biopharm & Drug Disp

View full text Add to dashboard Cite

Since previous studies suggested that baclofen absorption in the rat middle intestine was inhibited by beta-alanine and therefore mediated, at least in part, by the beta-aminoacid carrier, we focused our new studies on the analysis of the possible inhibition of the drug by a gamma-aminoacid model compound, gamma-aminobutyric acid (GABA). A rat jejunum in situ study was undertaken in order to evaluate the effect of GABA on baclofen absorption and to establish the inhibition model. Assays using isotonic perfusion solutions of 0.5 mM baclofen with starting GABA concentrations ranging from 0 to 100 mM are reported. The results show that the absorption rate pseudoconstants of the drug decrease at the GABA concentration increases, with a limiting value of 0.65 h-1 (+/- 0.01). A partial competitive inhibition or complete competitive inhibition in the presence of a passive component could define the interaction phenomena between the two substances. Kinetic absorption parameters for GABA in the presence and absence of baclofen (Ki = 5.67 +/- 1.54, Km = 3.87 +/- 0.63) suggest the existence of more than one intestinal carrier system for baclofen or GABA.

show abstract

Comparative Aspects of Amino Acid Ttansport in Guinea Pig, Rabbit and Rat Small Intestine

Cited by 9 publications

References 47 publications

Transport of neutral and cationic amino acids across the brush-border membrane of the rabbit ileum

Transport of neutral and cationic amino acids across the brush-border membrane of the rabbit ileum

Transport of imino acids and non-α-amino acids across the brush-border membrane of the rabbit ileum

Influence of γ‐aminobutyric acid on baclofen intestinal absorption

Contact Info

Product

Resources

About