scholarly journals AUTORADIOGRAPHIC STUDY OF SUGAR AND AMINO ACID ABSORPTION BY EVERTED SACS OF HAMSTER INTESTINE

1965 ◽  
Vol 25 (2) ◽  
pp. 19-39 ◽  
Author(s):  
William B. Kinter ◽  
T. Hastings Wilson
Keyword(s):  
Amino Acids ◽  
Brush Border ◽  
Basal Membrane ◽  
Autoradiographic Study ◽  
Border Region ◽  
Transport Systems ◽  
Frozen Sections ◽  
Basal Pole ◽  
Everted Sacs

Autoradiographs were prepared from frozen sections of everted sacs of hamster jejunum which had been incubated in vitro with C14- or H3-labeled sugars and amino acids. When such tissue was incubated in 1 mM solutions of L-valine or L-methionine, columnar absorptive cells at tips of villi accumulated these amino acids to concentrations ranging from 5 to 50 millimoles per liter of cells. Quantitative data were obtained by microdensitometry of C14 autoradiographs. Similar, though less striking, results were obtained with the sugars: galactose, 3-0-methylglucose, α-methylglucoside, and 6-deoxyglucose. In all cases the marked "step-up" in concentration occurred near the brush border of the cell, and a "step-down" in concentration occurred at the basal pole of the cell. Known inhibitors of intestinal absorption, e.g., phlorizin in the case of sugars, blocked the concentrative step at the luminal border of the absorptive cell. It is inferred from these data that active transport systems for sugars and amino acids reside in the brush border region of the cell. Additional evidence suggests that the basal membrane of the cell may be the site of both a diffusion barrier and a weak transport system directed into the cell.

Experimental Cystinuria: the Cycloleucine Model. I. Amino Acid Interactions in Renal and Intestinal Epithelia

1975 ◽  
Vol 53 (6) ◽  
pp. 1027-1036 ◽  
Author(s):  
André G. Craan ◽  
Michel Bergeron
Keyword(s):  
Amino Acids ◽  
Renal Tubules ◽  
Intestinal Epithelia ◽  
Luminal Membrane ◽  
Luminal Side ◽  
Convoluted Tubules ◽  
Dibasic Amino Acids ◽  
Everted Sacs

The injection of cycloleucine (1-aminocyclopentanecarboxylic acid (ACPC)) into rats produces a hyperexcretion of dibasic amino acids and cystine, an aberration resembling cystinuria. This may constitute a model of experimental cystinuria, and the transport of amino acids involved in this disease was studied with the techniques of everted intestinal sacs (in vitro) and microinjections into renal tubules (in vivo). In everted sacs from normal rats, there was a decrease in transfer and in accumulation of L-cystine (0.03 mM), L-lysine (0.065 mM) and L-valine (0.065 mM) when ACPC was on the mucosal (luminal) side. Dibasic amino acids such as L-ariginine and L-lysine caused a similar inhibition of the transport of L-cystine. However, when ACPC was on the serosal (antiluminal) side, a lesser effect was noted while arginine and lysine had no effect. Intestinal sacs from treated rats (ACPC, 300 mg/kg × 3 days) transferred and accumulated as much L-cystine as those from control rats. The interaction between cycloleucine and L-cystine was competitive at the luminal and non-competitive at the antiluminal side of the intestine. Cycloleucine inhibited L-lysine transport in a non-competitive fashion at either side of the intestine. L-Lysine also interacted in a non-competitive fashion with L-cystine transport at the luminal membrane. In proximal convoluted tubules, the presence of L-arginine or ACPC caused a decrease in the transport of L-cystine and L-lysine. L-Valine exerted no effect. Furthermore, L-lysine and ACPC did not impair the reabsorption of L-valine significantly.These results suggest a functional heterogeneity between luminal and antiluminal membranes of renal and intestinal epithelia and the existence, at both membranes, of different transport sites for cystine and dibasic amino acids.

Amino acid transport systems in intestinal brush-border membranes from lepidopteran larvae

1989 ◽  
Vol 257 (3) ◽  
pp. R494-R500 ◽  
Author(s):  
B. Giordana ◽  
V. F. Sacchi ◽  
P. Parenti ◽  
G. M. Hanozet
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Brush Border ◽  
Amino Acid Transport ◽  
Transport Systems ◽  
Acid Transport ◽  
Specific System ◽  
Neutral Amino Acids ◽  
Intestinal Brush Border ◽  
Lepidopteran Larvae

Experiments with intestinal brush-border membrane vesicles from lepidopteran larvae disclosed the occurrence of unique cotransporter proteins that use K+ as the driver cation for the transmembrane transfer of amino acids across the luminal border of midgut enterocytes. Six apical membrane amino acid transport systems have been identified. These systems are 1) a neutral amino acid transporter with a broad spectrum of interactions with most neutral amino acids, which is highly concentrative, strongly K+- and electrical potential-dependent, poorly stereospecific, and recognizes histidine, but not proline, glycine, or alpha-(methylamino)isobutyric acid (MeAIB); 2) a specific system for L-proline; 3) a specific system for glycine with a higher affinity for Na+ than for K+; 4) a specific system for L-lysine, which is dependent on membrane potential, is highly sensitive to external K+, and does not interact with L-arginine or neutral amino acids; 5) a specific K+-dependent process for glutamic acid, which does not recognize aspartic acid; and last, 6) an apparently unique K+- driven mechanism for D-alanine, which is potential-dependent and strongly stereospecific.

Na+-independent transport of bipolar and cationic amino acids across the luminal membrane of the small intestine

1997 ◽  
Vol 272 (4) ◽  
pp. R1060-R1068 ◽  
Author(s):  
B. G. Munck ◽  
L. K. Munck
Keyword(s):  
Amino Acids ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Short Circuit ◽  
Present System ◽  
Rabbit Ileum ◽  
Beta Alanine ◽  
Brown Adipose ◽  
Cationic Amino Acids

The role of sodium in transport of bipolar and cationic amino acids and their interactions were examined in vitro by measuring unidirectional influx across the brush-border membrane of intact rat jejunal and rabbit ileal epithelia. The chloride-dependent and beta-alanine inhibitable B(0,+) present in rabbit ileum was blocked by combining inhibition by beta-alanine with Na(+)- or Cl(-)-free conditions. Under these conditions, lysine influx across the brush-border membrane is Na+ independent. All Na+-independent influx of cationic and bipolar amino acids is by a system b(0,+) equivalent in the brush-border membrane of both species, where a system y+ is not present. System b(0,+) is shown to be a potent exchanger of intracellular leucine for extracellular lysine and of intracellular lysine for extracellular leucine. The model used to explain leucine stimulation of mucosa to serosa lysine transport can explain Na+ dependence of net lysine absorption. On the assumption that b(0,+) in situ, like the transporter induced by retroperitoneal brown adipose tissue in Xenopus laevi oocytes, acts as an obligatory exchanger, this model can also explain the effects of lysine on short-circuit current and net transport of sodium and the effect on transport capacity by preincubation at Na+-free conditions.

Intestinal transport of certain N-substituted amino acids

1962 ◽  
Vol 203 (4) ◽  
pp. 637-640 ◽  
Author(s):  
Hiroshi Hagihira ◽  
T. Hastings Wilson ◽  
Edmund C. C. Lin
Keyword(s):  
Amino Acids ◽  
Transport System ◽  
Intestinal Transport ◽  
Transport Systems ◽  
Concentration Gradients ◽  
Methyl Derivatives ◽  
Derivatives Of ◽  
Amino Acid Carrier ◽  
Everted Sacs

Sarcosine, N,N-dimethylglycine and betaine were transported against concentration gradients by everted sacs of hamster small intestine. These compounds shared a common transport system which differed from that which acted on most neutral l-amino acids. The N-methyl derivatives of glycine, while competing with each other, had no effect on the transport of l-valine. Furthermore, l-valine and l-methionine, which were powerful inhibitors of the transport of most other neutral l-amino acids, had little effect on the absorption of betaine. Two other N-substituted amino acids, l-proline and hydroxy-l-proline, possessed affinity for both transport systems, a greater affinity being shown for the betaine carrier than for the neutral amino acid carrier. It is postulated that the transport system for N-substituted amino acids is important for the absorption of l-proline and hydroxy-l-proline in vivo.

Ontogenesis of intestinal taurine transport: evidence for a beta-carrier in developing rat jejunum

1988 ◽  
Vol 254 (6) ◽  
pp. G870-G877 ◽  
Author(s):  
M. S. Moyer ◽  
A. L. Goodrich ◽  
M. M. Rolfes ◽  
F. J. Suchy
Keyword(s):  
Amino Acids ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Equilibrium Concentration ◽  
Membrane Vesicles ◽  
Transport Systems ◽  
Rat Jejunum ◽  
Adult Rats ◽  
Taurine Transport ◽  
Taurine Uptake

Taurine, a sulfur-containing beta-amino acid, may be conditionally essential during development. However, the existence of a carrier system for beta-amino acids has not been demonstrated in brush-border membrane vesicles (BBMV) from adult rat jejunum. We studied the uptake of [3H]taurine in BBMV prepared from the jejunum of developing and adult rats using a cation-precipitation technique. Uptake of 10 microM [3H]taurine by adult BBMV was slightly enhanced in the presence of an inwardly directed 100 mM Na+ gradient compared with a K+ gradient, and there was no intravesicular accumulation of isotope above the equilibrium concentration ("overshoot"). In contrast, taurine transport by BBMV from 10-day-old rat pups was markedly accelerated in the presence of a Na+ gradient compared with a K+ gradient and a twofold overshoot was observed. Na+-dependent taurine uptake was inhibited by the structural analogues hypotaurine and beta-alanine but not by alpha-alanine or glutamine, which are amino acids served by other transport systems. By computer analysis, Na+-dependent taurine uptake (2-1,000 microM) was saturable with an apparent Km of 74.80 +/- 11.87 microM and a Vmax of 53.55 +/- 2.76 pmol.mg protein-1.min-1. With increasing postnatal age, there was a marked decrease in the initial rate and peak intravesicular accumulation of taurine with disappearance of the overshoot by 21 days of age. We conclude 1) a Na+-dependent carrier mechanism for taurine transport is present in the brush-border membrane of suckling rat jejunum and 2) the activity of this carrier decreases after weaning.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of l-methionine and l-lysine uptake in chicken jejunal brush-border membrane by dietary methionine

1999 ◽  
Vol 277 (6) ◽  
pp. R1654-R1661 ◽  
Author(s):  
Juan F. Soriano-García ◽  
Mònica Torras-Llort ◽  
Miquel Moretó ◽  
Ruth Ferrer
Keyword(s):  
Amino Acids ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Transport Systems ◽  
Food Utilization ◽  
Maximal Velocity ◽  
Neutral Amino Acids ◽  
System L ◽  
Methionine Supplementation

In the chicken intestine,l-methionine is transported by systems that are specific for neutral amino acids (L- and B-like) and by systems that can also transport cationic amino acids (y+m and b0,+-like). These four uptake pathways have been investigated in brush-border membrane vesicles from the jejunum of chickens fed a diet enriched with 0.4%l-methionine. Methionine supplementation from the 1st to the 6th wk of age has no effect on body weight or on the efficiency of food utilization. The kinetic analysis of l-methionine influx across the transport systems specific for neutral amino acids shows, for system L, no dietary effect on the Michaelis constant ( K m) and a 30% reduction in maximal velocity ( V max); for system B it shows a decrease in K m (30%) and in V max (51%). Transport systems shared by cationic and neutral amino acids show no dietary effect on b0,+ activity and a significant reduction in y+m V max, similar forl-methionine andl-lysine, both in the absence and in the presence of Na+(l-methionine, 30 and 26% reduction; l-lysine, 19 and 28% reduction, respectively). The downregulation induced byl-methionine supplementation may be an adaptive response to reduce the risk of intoxication by dietary excess of l-methionine. These results support the view that the toxicity of the supplemented substrate can be an important factor in the regulation of amino acid transport by dietary content.

AMINO ACID TRANSPORT SYSTEMS IN BRUSH-BORDER MEMBRANE VESICLES FROM LEPIDOPTERAN ENTEROCYTES

1989 ◽  
Vol 143 (1) ◽  
pp. 87-100
Author(s):  
GIORGIO M. HANOZET ◽  
BARBARA GIORDANA ◽  
V. FRANCA SACCHI ◽  
PAOLO PARENTI
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Brush Border ◽  
Amino Acid Transport ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Transport Systems ◽  
Acid Transport ◽  
Luminal Membrane

The presence of different potassium-dependent amino acid transport systems in the luminal membrane of the larval midgut of Philosamia cynthia Drury (Saturnidae, Lepidoptera) was investigated by means of countertransport experiments performed with brush-border membrane vesicles. The vesicles were preloaded with 14 different unlabelled amino acids, whose ability to elicit an intravesicular accumulation over the equilibrium value of six labelled amino acids (L-alanine, L-leucine, L-phenylalanine, L-glutamic acid, L-lysine and L-histidine) was tested. For histidine, the results were compared with those obtained from inhibition experiments, in which the same 14 amino acids were used as inhibitors on the cis side of the brush-border membrane. The data demonstrate the presence in the lepidopteran luminal membrane of distinct transport pathways for lysine and glutamic acid. The transport of most neutral amino acids, with the exclusionof glycine and proline, seems to occur through a system that may be similar to the neutral brush-border system (NBB) found in mammalian intestinal membranes. This system is also able to handle histidine.

Two cationic amino acid transport systems in human placental basal plasma membranes

1991 ◽  
Vol 261 (2) ◽  
pp. C246-C252 ◽  
Author(s):  
T. C. Furesz ◽  
A. J. Moe ◽  
C. H. Smith
Keyword(s):  
Amino Acids ◽  
Time Course ◽  
Plasma Membranes ◽  
Membrane Vesicles ◽  
Basal Membrane ◽  
Transport Systems ◽  
Cationic Amino Acid ◽  
Basal Plasma ◽  
Cationic Amino Acids

Transport of cationic amino acids in basal (fetal facing) plasma membranes was investigated by characterization of L-[3H]lysine and L-[3H]arginine uptake in membrane vesicles isolated from term human placentas. At least two Na(+)-independent systems were present. Lysine concentration dependence data were fit by a two-system model with Km values of 1.0 +/- 0.8 and 223 +/- 57 microM and Vmax values of 0.06 +/- 0.03 and 24.0 +/- 5.8 pmol.mg protein-1.min-1. In the presence of either 10 mM L-leucine or Na+ plus 10 mM L-homoserine, the data were fit by single system models with kinetic parameters similar to the higher and lower Km systems seen in the absence of inhibitors. Uptake of 10 or 20 microM L-lysine in the absence of Na+ showed the higher Km system was inhibited completely by L-arginine, L-homoarginine, and L-histidine. In the presence of Na+, the higher Km system was inhibited completely by L-alanine, L-homoserine, L-leucine, L-phenylalanine, and L-norleucine. The lower Km system was inhibited completely by L-arginine, L-homoarginine, L-histidine, L-leucine, and L-methionine. Time course studies of uptake demonstrated that uptake by either system alone filled the total vesicular space. The basal membrane of human placental syncytiotrophoblast possesses two transport systems for lysine and arginine, resembling the ubiquitous y+ system and the bo,+ system previously described in mouse blastocysts. The higher Vmax of the y+ system suggests that in utero it may mediate transfer of cationic amino acids from the syncytiotrophoblast to the fetus. The role of the high-affinity low-capacity bo,+ system remains to be determined.

H+ gradient-driven dipeptide reabsorption in proximal tubule of rat kidney. Studies in vivo and in vitro

1987 ◽  
Vol 253 (3) ◽  
pp. F448-F457 ◽  
Author(s):  
S. Silbernagl ◽  
V. Ganapathy ◽  
F. H. Leibach
Keyword(s):  
Amino Acids ◽  
Proximal Tubule ◽  
Rat Kidney ◽  
High Capacity ◽  
Peptide Transport ◽  
Transport Systems ◽  
Negative Membrane Potential ◽  
Uptake Process

Microinfusion of glycylsarcosine into superficial nephron sections showed that the dipeptide was reabsorbed mainly in late portions of the rat proximal tubule. In vivo microperfusion data demonstrated a saturable, high-capacity, low-affinity dipeptide reabsorption mechanism that was inhibited by other peptides but not by amino acids or peptidase inhibitors. The reabsorption was enhanced by lowering the luminal pH from 7.5 to 5.5. In vitro studies with rat cortical brush-border vesicles showed that glycylsarcosine uptake was independent of a Na+ gradient and greater uptake occurred when the extravesicular pH was acidic compared with the intravesicular pH. An inward-directed H+ gradient stimulated glycylsarcosine uptake and caused a transient accumulation of the dipeptide inside the vesicles above the equilibrium value. The presence of a proton ionophore abolished the H+ gradient-dependent uptake. An inside-negative membrane potential stimulated the initial uptake of the dipeptide. The uptake process was saturable and inhibited by other peptides but not by amino acids. The vesicle studies also showed that there are at least two peptide transport systems functioning in these vesicles, one a high-affinity, low-capacity type and the other a low-affinity, high-capacity type.

Brush-border amino acid transport mechanisms in carnivorous eel intestine

1989 ◽  
Vol 257 (3) ◽  
pp. R506-R510 ◽  
Author(s):  
C. Storelli ◽  
S. Vilella ◽  
M. P. Romano ◽  
M. Maffia ◽  
G. Cassano
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Brush Border ◽  
Amino Acid Transport ◽  
Membrane Vesicles ◽  
Anguilla Anguilla ◽  
Neutral Amino Acid ◽  
Transport Systems ◽  
European Eel ◽  
Acid Transport

Brush-border membrane vesicles (BBMV) were prepared from European eel (Anguilla anguilla) intestinal epithelium by a magnesium-ethylene glycolbis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) precipitation technique. Amino acid transport by these purified vesicle preparations was investigated using either radiolabeled substrates or the voltage-sensitive fluorescent dye 3,3'-diethylthiadicarbocyanine iodide [DiSC2(5)]. All amino acids tested exhibited carrier-mediated, Na+-dependent and Na+-independent transfer processes plus diffusion. The only exceptions were glutamic acid and proline, which displayed Na+ dependency and diffusion but did not appear to be transported by Na+-independent agencies. Carrier-mediated transport kinetic constants (Kapp and Jmax) for several amino acids are reported. Cis-inhibition experiments suggested the presence of at least four distinct Na+-dependent transport systems in eel intestinal BBMV: 1) an anionic transport process for glutamic and aspartic acids; 2) a cationic mechanism for lysine and arginine; 3) a relatively specific neutral amino acid carrier for proline and alpha-(methylamino)isobutyric acid; and 4) a nonspecific neutral amino acid system for most other substrates of this group. This scheme for carnivorous fish intestine most closely approximates that reported for mammalian gut with minor dissimilarities that may relate to metabolic differences or specific dietary requirements of the two vertebrate groups.

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