Intestinal Amino Acid Transport Research Articles

Effect of theophylline and Na + on methionine influx in Na +-depleted intestine

The unidirectional influx of methionine into the brush border epithelium of chicken jejunum has been studied. Tissues leached of Na + transport methionine from a medium devoid of Na + with reduced apparent affinity ( K t) and maximal flux ( J max). Addition of Na + to the medium during a 1-min incubation with substrate, or during a 30-min preincubation, restored K t but affected J max slightly. Theophylline was found to maintain J max in the absence of Na +. Essentially complete restoration of K t and J max could be attained when theophylline-treated tissue was exposed to Na + for 30 min. Influx from a Na + medium was unaffected by theophylline pretreatment in Na +-containing buffer. K t was increased without an effet upon J max when influx was studied from choline medium following preincubation in Na +. Modifiers of tissue cyclic AMP levels were investigated in conjunction with theophylline. Histamine and carbachol were found to inhibit theophylline-stimulated transport. Secretin was found to stimulate influx in Na +-leached tissue, but did not potentiate the theophylline effect. Amino acids in the incubation medium inhibited theophylline-stimulated influx, whereas preloaded lysine or methionine had no effect. The results are interpreted in terms of a model which envisions roles for cellular and external Na + and for cyclic AMP in the activation and regulation of amino acid transport in intestine.

Effect of vitamin D deficiency on aminoaciduria and intestinal transport of amino acids in the rat.

Generalized hyperaminoaciduria and hyperphosphaturia are associated with human vitamin D deficiency rickets and the effect has been reproduced in animals. The basis for the renal transport impairment was attributed to secondary hyperparathyroidism resulting from hypocalcemia.In this study we attempted over a 16-week period to induce hyperaminoaciduria in Holtzman rats with vitamin D deficient diets of varying calcium content (0.4% and 0.04%) so as to investigate the possibility of a concomitant defect in intestinal transport of amino acids. Despite signs of secondary hyperparathyroidism, generalized hyperaminoaciduria was not in evidence in any of the groups. However, increased urinary excretion of lysine and taurine was demonstrated in rats fed a low calcium diet without vitamin D (LCa−D). The same observation was also made for taurine in rats deprived of vitamin D and on a normal calcium diet (NCa−D) and in animals fed a low calcium diet with vitamin D (LCa+D). The results failed to show any effect of vitamin D deficiency, hypocalcemia, or secondary hyperparathyroidism on the intestinal transport of lysine, alanine, and cycloleucine.

Intestinal transport of aromatic amino acids, glucose and electrolytes in a patient with phenylketonuria

The intestinal transport of aromatic amino acids, glucose and electrolytes was studied with a double lumen transintestinal tube in a phenylketonuric female, when her plasma phenylalanine level was 1.87 mM and at the end of one month on a low-phenylalanine intake when her plasma phenylalanine was 0.84 mM. Three healthy adult volunteers served as controls. Their plasma phenylalanines were below 0.16 mM. Jejunal perfusions were performed using isotonic buffers with either 1, 2 or 5 mM l-phenylalanine, 1 mM l-tryptophan, 1 mM l-tyrosine or one which was amino acid-free. All solutions included 40 mM glucose and 600 mg% of polyethylene glycol mol. wt 3000−3700 as a non-absorable marker. The intestinal absorption rates in the phenylketonuric were significantly below those of the volunteers for l-phenylalanine (−4.3 to −18.1%), l-tryptophan (−9.6%), glucose (−10.3%), and sodium (−40.9%). However, they were higher than in the controls for l-tyrosine and potassium. When circulating phenylalanine was reduced by dietary treatment in the phenylketonuric patient, the transport of l-phenylalanine, l-tryptophan and sodium became at least as high as that in normal individuals. Glucose absorption remained at lower levels.

Distinct components of neutral amino acid transport in chick small intestine

1. 1. The intestinal absorption of alanine, β-alanine, α-aminoisobutyric acid (AIB), glycine, proline and tryptophan has been studied by an in vitro tissue accumulation method in the chick. 2. 2. The use of amino acids as specific blocking agents allowed for the characterization of seven discrete components of neutral amino acid transport which can be grouped into three major categories: (a) those processes inhibited by leucine and glycine; (b) those inhibited by leucine, but not by glycine; (c) those not inhibited by leucine.

Lowe's syndrome. Absence of amino acid transport defect in cultured fibroblasts.

SUMMARYTransport of lysine and glycine was studied in cultured fibroblasts of a patient with Lowe's oculocerebrorenal syndrome. Although patients with this syndrome demonstrate renal and intestinal amino acid transport defects, no abnormality was found in our study.

Inhibition of amino acid transport in rabbit intestine by p-chloromercuriphenyl sulfonic acid.

Influx of phenylalanine across the brush border of rabbit intestine is markedly reduced by treatment with 5 mM p-chloromercuriphenyl sulfonate (PCMBS). The effect is rapidly and completely reversed by dithiothreitol. Phenylalanine influx into PCMBS-treated tissue can be competitively inhibited by other neutral amino acids and follows saturation kinetics. PCMBS causes an increase in the apparent Michaelis constant from the value observed in control tissue but does not alter the maximal influx significantly. Treatment of the tissue with PCMBS leads to a significant reduction in the Na-sensitivity of the transport, and a number of results indicate that the major effect of the reagent is to cause a marked reduction in the affinity of the transport system for Na. The transport system can be partially protected against reaction with PCMBS by phenylalanine and tryptophan but not by methionine or norleucine. The results suggest that PCMBS reacts with a sulfhydryl group in the region of the transport site and may alter conformational changes associated with the binding of substrates.

The role of energy metabolism in the interaction between amino acid and sugar transport in the small intestine.

The interaction between sugar and amino acid transport was studied in everted sacs of rat jejunum in vitro. The addition of the actively transported nonmetabolized sugars, D-galactose and α-methyl-D-glucoside, to the mucosal medium inhibited the active transport of cycloleucine (1-amino-cyclopentane-1-carboxylic acid). This effect was largely counteracted by the simultaneous presence of D-glucose in the serosal medium or of D-fructose. The results indicate that provision of substrates for energy metabolism relieves the inhibition of transport and supports the hypothesis that the interaction between the intestinal transport of sugar and of amino acid is at least in part due to competition for a limited supply of metabolic energy.

Chronic glucagon administration enhances intestinal transport in the rat.

SummaryHyperglucagonemia, induced experimentally in rats by 6-hourly injections of glucagon, resulted in increased intestinal transport of amino acids and sugar as measured by the everted ring technique. Glucagon administration enhanced both accumulation and rate of uptake into the intestinal rings. The effect was observed after a lag of 2 days and increased thereafter with the length of treatment. Glucagon added in vitro was without effect.This experimental system, like diabetes and partial starvation, provides a technique for studying the effect of relative or absolute hyperglucagonemia on the intestine.

Inhibition of intestinal amino acid transport by blood sugar lowering biguanides.

The effect of blood-glucose lowering biguanides (phenethyl- and butylbiguanide) on active intestinal transport of different amino acids has been tested in hamster small intestinein vitro. —.Biguanides inhibited active transport of all amino acids tested. The inhibitory effect of biguanides increased with incubation time, was more pronounced after preincubation of intestinal tissue and was found to be non-competitive. The minimal inhibitory concentration of phenethylbiguanide on amino acid transport was 5×10−4 M. —14C-butylbiguanide was found to be transported into hamster small intestine by a concentration-independent, energy-independent uptake mechanism and was accumulated in intestinal tissue against a concentration gradient. — In accord with earlier results on the inhibitory effect of biguanides on active intestinal hexose transport it is concluded that biguanides do not act as specific inhibitors for glucose transport, but rather affect active, energy-requiring intestinal transport mechanisms in general (hexose-, amino acid-, calcium- and myo-inositol transport), most likely due to their known inhibitory effect on mitochondrial respiration, thus depriving mucosal cells of ATP required to translocate substrates against a concentration gradient.

Intracellular Cl concentrations and influxes across the brush border of rabbit ileum

Intracellular Cl concentrations and influxes across the brush border of rabbit ileum

Intestinal amino acid transport and tissue concentrations in diabetes

Intestinal amino acid transport and tissue concentrations in diabetes

Hyperaminoacidemia effects on intestinal transport of related amino acids.

ARTICLESHyperaminoacidemia effects on intestinal transport of related amino acidsRA Wapnir, RL Hawkins, and F LifshitzRA Wapnir, RL Hawkins, and F LifshitzPublished Online:01 Oct 1972https://doi.org/10.1152/ajplegacy.1972.223.4.788MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByProfiling of faecal water and urine metabolites among Papua New Guinea highlanders believed to be adapted to low protein intake31 July 2017 | Metabolomics, Vol. 13, No. 9Tyrosine supplementation in phenylketonuria: Diurnal blood tyrosine levels and presumptive brain influx of tyrosine and other large neutral amino acidsThe Journal of Pediatrics, Vol. 139, No. 3Response in hepatic removal of amino acids by the sheep to short-term infusions of varied amounts of an amino acid mixture into the mesenteric vein9 March 2007 | British Journal of Nutrition, Vol. 85, No. 6Regulation of l-methionine and l-lysine uptake in chicken jejunal brush-border membrane by dietary methionineJuan F. Soriano-García, Mònica Torras-Llort, Miquel Moretó, and Ruth Ferrer1 December 1999 | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Vol. 277, No. 6Effects of Oral Administration of Artificial Cells Immobilized Phenylalanine Ammonia-Lyase on Intestinal Amino Acids of Phenylketonuric Rats11 July 2009 | Biomaterials, Artificial Cells and Artificial Organs, Vol. 17, No. 2Increased neurotransmitter biosynthesis in phenylketonuria induced by phenylalanine restriction or by supplementation of unrestricted diet with large amounts of tyrosineEuropean Journal of Pediatrics, Vol. 148, No. 3The Regulation of Amino Acid and Sugar Absorption by Diet27 April 2009 | Nutrition Reviews, Vol. 42, No. 7Effects of Dietary Protein Level and Ascorbic Acid Supplementation on the Contents of Tyrosine Metabolites in Droppings and Plasma of Chicks Fed a Diet Containing Excess TyrosinePoultry Science, Vol. 62, No. 12Tyrosine supplementation in chronic experimental uremiaBiochemical Medicine, Vol. 30, No. 1Disorders of Nitrogen AbsorptionClinics in Gastroenterology, Vol. 11, No. 1Intensified gradients for endogenous amino acid substrates for transport system L on injecting a specific competitor for that systemLife Sciences, Vol. 29, No. 7Digestion in the pig between 7 and 35 d of age9 March 2007 | British Journal of Nutrition, Vol. 45, No. 2The regulation of amino acid transport in animal cellsBiochimica et Biophysica Acta (BBA) - Reviews on Biomembranes, Vol. 515, No. 4Kinetics of the absorption of amino acids by the rat intestine in vivoBiochimica et Biophysica Acta (BBA) - Biomembranes, Vol. 512, No. 1Amino acid uptake in chickens subjected to increasing levels of quantitative food restriction9 March 2007 | British Journal of Nutrition, Vol. 38, No. 3Developmental patterns of intestinal transport mechanisms in the chickComparative Biochemistry and Physiology Part A: Physiology, Vol. 54, No. 1l-phenylalanine interactions with structurally related substances at the intestinal mucosaBiochemical Medicine, Vol. 11, No. 4Intestinal transport of aromatic amino acids, glucose and electrolytes in a patient with phenylketonuriaClinica Chimica Acta, Vol. 54, No. 3 More from this issue > Volume 223Issue 4October 1972Pages 788-793 Copyright & PermissionsCopyright © 1972 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1972.223.4.788PubMed4263024History Published online 1 October 1972 Published in print 1 October 1972 Metrics

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

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

Amino acid transport by rat small intestine galactose inhibition of transepithelial net transport as a result of stimulation of bidirectional efflux from the epithelium

1. 1. The effects of galactose on jejunal and ileal transport of amino acids have been reexamined. Influx across the brush border membrane ( J me) steady-state epithelial uptake [ A] c and steady-state unidirectional transmural fluxes ( J ms′ J sm) have been measured. Both leucine and proline have been used. 2. 2. J mc and J ms were found to be unaffected but [ A] c was markedly reduced and J sn, just as markedly increased. 3. 3. It is concluded that the apparently inhibitory effects of galactose on intestinal amino acid transport result from a galactose-induced stimulation of amino acid efflux across the brush border membrane and across the serosal face of the epithelial cell membrane. 4. 4. Attention is called to the possibility that these effects are specific for the in vitro situation. Only if this is not the case should the possibility of cooperative interactions between sugars, amino acids and their carriers be seriously reconsidered. 5. 5. It is shown that everted rat jejunum sacs as far as amino acid transport is concerned, maintain their functional integrity for more than 180 min.

Toxicology of PCBs for Mammals and for Birds

Toxicology of PCBs for Mammals and for Birds

Toxicology of PCBs for Mammals and for Birds

Toxicology of PCBs for Mammals and for Birds

Adaptation of intestinal amino acid transport.

An evertierten Dunndarmsacken (proximales Jejunum) erwachsener Ratten, die zwei Wochen lang eine proteinarme (13% Kasein) oder proteinreiche (88% Kasein) Diat erhalten hatten, wurde der aktive intestinale Transport vonl-Leuzin undd-Galaktose untersucht. Proteinreiche Ernahrung fuhrte zu einer Stimulierung desl-Leuzin-Transports, wahrend derd-Galaktose-Transport dadurch unbeeinflusst blieb. Diese Befunde sprechen fur eine spezifische Adaptation des intestinalen Aminosaurentransports an den Proteingehalt der Nahrung.

Amino acid transport by rat small intestine. Galactose inhibition of transepithelial net transport as a result of stimulation of bidirectional efflux from the epithelium.

1. 1. The effects of galactose on jejunal and ileal transport of amino acids have been reexamined. Influx across the brush border membrane ( J me ) steady-state epithelial uptake [ A ] c and steady-state unidirectional transmural fluxes ( J ms′ J sm ) have been measured. Both leucine and proline have been used. 2. 2. J mc and J ms were found to be unaffected but [ A ] c was markedly reduced and J sn , just as markedly increased. 3. 3. It is concluded that the apparently inhibitory effects of galactose on intestinal amino acid transport result from a galactose-induced stimulation of amino acid efflux across the brush border membrane and across the serosal face of the epithelial cell membrane. 4. 4. Attention is called to the possibility that these effects are specific for the in vitro situation. Only if this is not the case should the possibility of cooperative interactions between sugars, amino acids and their carriers be seriously reconsidered. 5. 5. It is shown that everted rat jejunum sacs as far as amino acid transport is concerned, maintain their functional integrity for more than 180 min.

Developmental Pattern of Sugar and Amino Acid Transport in the Postnatal Rat Small Intestine

Extract: The transport of two sugars and three amino acids by proximal and distal intestinal segments of 2-, 5-, 10-, 16-, 22-, 26-, 30-, and 70− to 84-day-old rats was investigated. Labeled α-methyl-D-glucoside and D-galactose were the sugars and labeled L-valine, L-lysine, and glycine were the amino acids used. The sugars were selected because they are thought to share a common transport system in the adult rat. Conversely, the three amino acids were selected because they appear to have separate transport systems in the adult rat. Intracellular accumulation was the transport variable investigated. Transport of both sugars and the three amino acids was maximal in early postnatal life (period I; 2–5 days); however, the patterns of decrease in transport to adult levels showed marked variation. The pattern of decrease for both sugars as well as valine was similar, with about 50% of the total decrease occurring between periods I and II (10–16 days), about 33% between periods II and III (22–30 days), and 15–20% between periods III and IV (70–80 days). The well established predominance of the proximal intestine in sugar transport was not observed until period III. Lysine showed a relatively small decrease, 10%, between periods I and II, the largest decrease between periods II and III, 56.4%, and a decrease between periods III and IV nearly twice as large as the decrease of any other compound at the comparable age span. Glycine exhibited approximately 70% of its total decrease between periods I and II. The 15% decrease in glycine transport between periods II and III was less than one-half that shown by any of the other compounds during the same period. These developmental data give further support to the thesis of separate transport systems for neutral, basic, and glycine-preferring amino acids. Speculation: This study reveals that protein and carbohydrate digestion end products are maximally transported at or shortly after birth. Further, we believe that significant physiologic data may be obtained from the study of the postnatal developmental patterns of digestive processes

Studies of Intestinal Transport Defect in Hartnup Disease

Hartnup disease was discovered in two brothers as a result of a survey for amino acid disorders. Two unaffected brothers and a series of control subjects were also studied. Intestinal amino acid transport was measured by in vivo and in vitro techniques. In the affected brothers tryptophan and phenylalanine transport were defective, methionine transport was abnormal in one of the two, and leucine, lysine, and proline transport were normal in vivo. The transport of methionine and tryptophan by mucosal segments in vitro was markedly reduced in the affected brothers in whom these studies were performed. In both affected brothers transport of lysine and glycine in vitro was minimally reduced and correlated with modest increases of these amino acids in the urine. Measurements of stool indoles and urine indican revealed elevation in both brothers after oral tryptophan loading. The defect in neutral amino acid transport seen in the intestine in Hartnup disease is demonstrable in vitro. Further studies are required to correlate transport in vitro, with absorption in vivo and with the aminoaciduria.