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Mahran YYFK, Khalifa AE, El-Demerdash E. A comparative study of protective mechanisms of glycine and L-arginine against cisplatin-induced nephrotoxicity in rat renal cortical slices. Drug Discov Ther 2011; 5:32-40. [DOI: 10.5582/ddt.v5.1.32] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Yasmen YFK Mahran
- Pharmacology & Toxicology Department, Faculty of Pharmacy, Ain Shams University
| | - Amani E Khalifa
- Pharmacology & Toxicology Department, Faculty of Pharmacy, Ain Shams University
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Scalera V, Mola MG, Prezioso G. The kinetic mechanism of the glutamate-aspartate carrier in rat intestinal brush-border membrane vesicles: the role of potassium. J Bioenerg Biomembr 2002; 34:95-103. [PMID: 12018893 DOI: 10.1023/a:1015171824847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The sodium dependent transport system for L-glutamate and L-aspartate localized in the apical part of rat enterocytes has previously been kinetically characterized (Prezioso, G., and Scalera, V. (1996). Biochim. Biophys. Acta 1279, 144-148). In this paper the mechanism by which the potassium cation specifically activates the L-glutamate-sodium cotransport process is investigated. Potassium has been found to act as an activator when it is present inside the membrane vesicles, while its presence outside is ineffective, and the effect is saturable. The kinetic parameters with respect to sodium and glutamate have been compared in the presence and in the absence of the activator. The results indicate that the ordered sodium-sodium glutamate mechanism is not altered by potassium, and that the activation is probably exerted on both the rate determining steps of the transport process. It is proposed that (1) a specific binding site for potassium is present on the inside hydrophilic part of the membrane carrier, (2) the binding of the effector accelerates the intramembrane rearrangement steps of both the disodium glutamate-carrier complex and the free carrier, (3) the affinity of the carrier is lowered with respect to sodium whereas it is increased for glutamate, and (4) K+ antiport is not performed by this carrier.
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Affiliation(s)
- V Scalera
- Dipartimento di Fisiologia Generale ed Ambientale, Università degli Studi di Bari, Italy.
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Zelikovic I, Budreau-Patters A. Cl- and membrane potential dependence of amino acid transport across the rat renal brush border membrane. Mol Genet Metab 1999; 67:236-47. [PMID: 10381331 DOI: 10.1006/mgme.1999.2866] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The relative roles of the anion present and the membrane potential in the operation of each of the seven amino acid transport systems in the renal tubular brush border membrane were explored by manipulating transmembrane potential and chemical gradients across the membrane. The effect of various external anions with different permeabilities of the membrane and of valinomycin-generated K+ diffusion potential on Na+-coupled amino acid accumulation by rat renal brush border membrane vesicles was examined. Accumulation of all amino acids examined, except for cystine, was membrane potential dependent. The highest voltage dependence was observed for taurine (equivalent to glucose) and l-methionine. Addition of taurine uptake values obtained under each electrical gradient (inside negative) and a chemical gradient (100 mM NaCl out) condition yielded markedly lower values than under conditions where there was a combined electrochemical gradient. Cl- gradient rather than merely imposing a voltage gradient was a specific mediator of Na+-coupled transport of l-proline, taurine, l-glutamic acid, and glycine across the brush border membrane. Cl- gradient alone under Na+-equilibrated conditions could energize an overshoot of taurine accumulation by vesicles providing evidence that taurine is energetically activated by and coupled to Cl- transport. These data suggest that Na+-linked transport of most amino acids across the tubular luminal membrane is an electrogenic positive process and for proline, taurine, glutamic acid, and glycine, a Cl--requiring process. A negative intracellular potential combined with luminal chloride is required for optimal Na+-coupled transport of these amino acids across the luminal membrane of the proximal tubule. The coupling of Cl- to the transport of these osmoprotective amino acids may enhance their volume regulatory effect in kidney cells and other mammalian cells.
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Affiliation(s)
- I Zelikovic
- Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington, USA.
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Prezioso G, Scalera V. Sequential ordered mechanism for the sodium-glutamate transport in intestinal brush border membrane vesicles. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1279:144-8. [PMID: 8603080 DOI: 10.1016/0005-2736(95)00262-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The glutamate/aspartate carrier localized in the brush-border membrane vesicles from enterocytes is known as a transport system catalyzing a sodium-substrate cotransport driven by the sodium gradient across the membrane. The kinetics of this transport system is studied by analogy with an enzymatic bi-substrate reaction. The results of this approach can be summarized as follows: (1) The dependence of the L-glutamate transport rate on the sodium concentration is sigmoidal, and the stoichiometry of the transport is 2 Na+/1 glutamate/1 carrier molecule. (2) The mechanism is sequential ordered, with L-glutamate binding after both the sodium cations. In addition, there is a very high degree of cooperativity between the two sodium binding sites.
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Affiliation(s)
- G Prezioso
- Dipartimento Farmaco-biologico, Università degli Studi di Bari, Italy
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Munck LK. Chloride-dependent amino acid transport in the small intestine: occurrence and significance. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1241:195-213. [PMID: 7640296 DOI: 10.1016/0304-4157(95)00005-c] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The unidirectional influx of amino acids, D-glucose and ions across the brush-border membrane of the small intestine of different species has been measured in vitro with emphasis on characterization of topographic and species differences and on chloride dependence. The regional differences in transport along the small intestine are outlined and shown to be caused by variation in transport capacity, while the apparent affinity constants are unchanged. Rabbit small intestine is unique by exhibiting maximal rates of transport in the distal ileum and a very steep decline in the oral direction from where tissues are normally harvested for preparation of brush-border membrane vesicles. Transport in the guinea pig and rat is much more constant throughout the small intestine. Since the capacity of nutrient carriers is regulated by their substrates it is possible that bacterial breakdown of peptides and proteins in rabbit distal ileum increases the concentration of amino acids leading to an upregulation of the carriers. Chloride dependence is a characteristics of the carrier rather than the transported amino acid, and is used to improve the classification of amino acid carriers in rabbit small intestine. In this species the imino acid carrier, the beta-amino acid carrier, and the beta-alanine carrier, which should be renamed the B0,+ carrier, are chloride-dependent. The steady-state mucosal uptake of classical substrates for these carriers in biopsies from the human duodenum is also chloride-dependent. The carrier of beta-amino acids emerges as ubiquitous and chloride-dependent, and evidence of cotransport with both sodium and chloride is reviewed. A sodium:chloride:2-methyl-aminoisobutyric acid coupling stoichiometry of approx. 2:1:1 is suggested by ion activation studies. Direct measurements of coupled ion fluxes in rabbit distal ileum confirm that sodium, chloride and 2-methyl-aminoisobutyric acid are cotransported on the imino acid carrier with an identical influx stoichiometry. Control experiments and reference to the literature on the electrophysiology of the small intestine exclude alterations of the membrane potential as a feasible explanation of the chloride dependence. Thus, it is concluded that chloride is cotransported with both sodium and 2-methyl-aminoisobutyric acid across the brush-border membrane of rabbit distal ileum.
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Affiliation(s)
- L K Munck
- Department of Medical Physiology, Panum Institute, University of Copenhagen, Denmark
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Abstract
Changes in tubular reabsorption of amino acids and other solutes are characteristic of the immature renal tubule and of various hereditary nephropathies. The cellular mechanisms governing these aberrations in renal amino acid transport have not been established. Calcium (Ca2+)-dependent protein kinases are known to phosphorylate membrane-bound carrier proteins, thereby modulating transport of various solutes by the proximal tubule. The role of these enzymes in regulating renal tubular amino acid transport, particularly during kidney development, is unknown. We investigated: (1) the effect of Ca(2+)- and phospholipid-dependent protein kinase [protein kinase C (PKC)] and Ca2+/calmodulin-dependent protein kinase II (CaMKII) on sodium chloride (NaCl)-linked proline transport by renal brush border membrane vesicles (BBMV) from adult rats using the "hypoosmotic shock" technique (lysis of vesicles); (2) the activity, expression and subcellular distribution (cytosol, particulate, BBM) of Ca(2+)-dependent protein kinases in kidneys from 7-day-old and adult rats using MBP 4-14 and autocamtide II phosphorylation assays for PKC and CaMKII, respectively, endogenous protein phosphorylation (using gel electrophoresis and autoradiography) and Western immunoblot analysis to detect PKC and CaMKII. The studies showed: (1) endogenous (membrane-bound) CaMKII and PKC as well as exogenous, highly purified PKC inhibit proline uptake by phosphorylated, lyzed/resealed BBMV when compared with control vesicles; the voltage-clamped, nonelectrogenic component of proline transport was inhibited by PKC- but not CaMKII-mediated phosphorylation; (2) a Ca(2+)-dependent activity of both kinases was evident in all subcellular fractions tested in immature and adult kidneys.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- I Zelikovic
- Department of Pediatrics, University of Washington, Seattle
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Heyman SN, Spokes K, Egorin MJ, Epstein FH. Glycine reduces early renal parenchymal uptake of cisplatin. Kidney Int 1993; 43:1226-8. [PMID: 8315935 DOI: 10.1038/ki.1993.173] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We evaluated the effect of glycine infusions on the early renal uptake of cisplatin, measured one hour after cisplatin was injected, as well as five days following cisplatin administration. Glycine (1.25 mmol per 100 g body wt) markedly attenuated the early uptake of platinum by the kidney, an effect not observed with control infusions of saline or of L-alanine. The kidney content of platinum at five days, on the other hand, was similar in glycine-treated animals and saline controls. Early inhibition of renal uptake of platinum may be responsible for glycine's protective action in experimental cisplatin nephrotoxicity.
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Affiliation(s)
- S N Heyman
- Charles A. Dana Research Institute, Department of Medicine, Harvard Medical School, Boston, Massachusetts
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Nutrient transport in fish: Studies with membrane vesicles. ACTA ACUST UNITED AC 1993. [DOI: 10.1029/ce043p0139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Sacchi VF, Magagnin S. Age-related modifications of leucine uptake in brush-border membrane vesicles from rat jejunum. Mech Ageing Dev 1992; 63:257-73. [PMID: 1614225 DOI: 10.1016/0047-6374(92)90004-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Leucine uptake in brush-border membrane vesicles purified from rat jejunum is sodium-dependent, sensitive to the membrane electrical potential difference and enhanced by the intravesicular presence of potassium. This last effect is not mediated by the genesis of an electrical potential difference, since potassium activation and electrical potential effects are additive. Sodium-dependent leucine Vmax (1568 +/- 91 pmol/mg per 3 s, is higher in young rats than in adult and old animals. The diffusion component of leucine transport decreases with increasing age. Preloading the vesicles with 100 mM KCl increases leucine Vmax 200% in young animals, 100% in adult and 44% in old animals. The potassium activation is a saturation function of the cation concentration. Leucine uptake in brush border membrane from old animals is less sensitive to the electrical potential difference than in membranes from adult and young animals.
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Affiliation(s)
- V F Sacchi
- Istituto di Fisiologia Generale e di Chimica Biologica, Università di Milano, Italy
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Munck LK, Munck BG. Chloride-dependence of amino acid transport in rabbit ileum. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1027:17-20. [PMID: 2118806 DOI: 10.1016/0005-2736(90)90041-l] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Chloride-dependence of influx across the brush-border membrane of distal rabbit ileum was examined for beta-alanine, 2-methylaminoisobutyric acid (MeAIB), leucine, lysine, proline and D-glucose. Influx of leucine at 2 mM and of D-glucose at 0.5 mM was chloride-independent indicating that substitution of isethionate for chloride has no unspecific effect on sodium gradient driven transport processes. In contrast influx of beta-alanine and MeAIB was totally dependent on the presence of chloride ions. In the absence of chloride, proline transport was reduced to 20% of its control level. This remaining transport can be accounted for by the function of the carrier of alpha-amino-monocarboxylic acids. Transport of leucine at 0.1 mM was reduced by absence of chloride. This is in accordance with the observation of leucine transport by the beta-alanine carrier. The kinetics of chloride and sodium activation of transport of MeAIB were examined at 1 mM MeAIB. Chloride activation was characterized by a Hill coefficient of 1 and a K1/2 of 23.5 mM, and sodium activation by a Hill coefficient of 2 and a K1/2 of 51 mM. Thus cotransport of chloride with an imino acid would be compatible with the known rheogenic nature of this transport. This study adds the imino acid carrier and the beta-alanine carrier to the group of chloride-dependent, epithelial amino acid transport systems.
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Affiliation(s)
- L K Munck
- Bispebjerg Hospital, Department of Medicine B, University of Copenhagen, Denmark
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Chesney RW, Zelikovic I, Jones DP, Budreau A, Jolly K. The renal transport of taurine and the regulation of renal sodium-chloride-dependent transporter activity. Pediatr Nephrol 1990; 4:399-407. [PMID: 2206910 DOI: 10.1007/bf00862526] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A model for the beta-amino acid taurine transport is presented to help define the ionic, pH, and voltage requirements for the movement of taurine into the rat proximal tubule brush border membrane vesicle (BBMV). Sodium-(Na+)-taurine symport across the apical surface of the proximal tubule has a highly specific requirement for Cl- and Br-. Active taurine transport operates with a 2 Na+:1 Cl-:1 taurine-carrier complex. Complexes like the one required for maximal taurine transport may be pertinent for many other amino acids whose uptake is Na(+)-dependent. Renal epithelial cell lines LLC-PK and MDCK were used to define the nature of taurine uptake; they express Na(+)-Cl(-)-taurine cotransport that is inhibited by beta-alanine. The cell lines up- or down-regulate taurine transport in response to changes in the taurine concentration of the medium in a manner similar to that seen in BBMV. The adaptation is present by 12 h and depends on new protein synthesis and protein import to the cell membrane. The role of trafficking in the adaptive response was also explored in brush border vesicles. During dietary surfeit, transporter could be down-regulated and transporters could be shifted back into the microtubule system, resulting in taurinuria. Use of continuous renal cell lines allowed a more mechanistic exploration of intracellular trafficking in the up- and down-expression of the Na(+)-Cl(-)-taurine cotransporter. Colchicine appeared to be a more potent inhibitor of the rapid (over hours) adaptive response to a reduction in media and, therefore, intracellular taurine content.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R W Chesney
- Department of Pediatrics, University of Tennessee, Memphis, 38103
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Abstract
The reabsorption of amino acids by the proximal tubule is remarkably efficient. Current evidence indicates that this process occurs by Na+-amino acid cotransport or symport. The energy for amino acid entry is derived from the chemical and voltage gradient for Na+ entry across the apical surface of the renal cell maintained by pumping Na+ out of the cell by Na+-K+-adenosine triphosphatase (ATPase) activity at the basolateral membrane. We chose the beta-amino acid taurine to study the anionic requirements as well as voltage- and pH-dependence of Na+-taurine symport into rat proximal tubule brush border membrane vesicles. Maximal uptake was found when Cl- or Br- were the anions. The addition of various ionophores (amiloride, carbonyl cyanide-n chlorophenyl-hydrazone, and valinomycin) under pH-equilibrated conditions did not change taurine entry into the vesicle. Hill equation analysis of the initial rate of taurine uptake into vesicles indicates that transport operates by means of a 2 Na+:1 Cl-:1 taurine-carrier complex. Because taurine is a zwitterion, this complex has a net positive charge. Its entry into the vesicle is favored by the imposition of an outwardly directed K+ gradient in the presence of valinomycin. The movement of a quaternary complex of this type across the apical surface of the proximal tubular cell would assure that the movement of both Cl- and the amino acid is energized by the Na+ gradient. Because most amino acids are zwitterions at physiologic pH this complex would be positively charged, favoring entry into the voltage negative renal cell interior.
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Affiliation(s)
- I Zelikovic
- Department of Pediatrics, University of Tennessee, College of Medicine, Memphis
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Abstract
Amino acids are reabsorbed from the tubular lumen by a saturable, carrier-mediated, concentrative transport mechanism driven by a Na+ electrochemical gradient across the luminal membrane. This process is followed by efflux mainly via carrier-mediated, Na+-independent facilitated diffusion across the basolateral membrane. Individual amino acids may have two or more Na+-dependent transport systems with different kinetic characteristics along the luminal membrane of the proximal tubule, thereby enabling very efficient amino acid reabsorption. Dual Na+-coupled transport pathways for some amino acids located in both the luminal and the peritubular membranes may operate in concert to provide the tubular epithelial cell with essential nutrients. One or more Na+ ions, H+, Cl- and in the case of acidic amino acids, K+ ion, may be involved in the translocation of the carrier complex. For most amino acids this process is electrogenic positive, favored by a negative cell interior. At least seven distinct, but largely interacting, Na+-dependent amino acid transport systems have been identified in the brush border membrane. A diet-induced adaptation in Na+-coupled taurine transport and acidosis-induced adaptive response in Na+-dependent glutamine transport are expressed at the luminal and the basolateral membrane surfaces, respectively. The aminoaciduria of early life may be related to a rapid dissipation of the Na+ electrochemical gradient necessary for amino acid reabsorption.
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Affiliation(s)
- I Zelikovic
- Department of Pediatrics, University of Tennessee, College of Medicine, Memphis
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Law RO. An inwardly-directed sodium-amino acid cotransporter influences steady-state cell volume in slices of rat renal papilla incubated in hyperosmotic media. Pflugers Arch 1988; 413:43-50. [PMID: 3217226 DOI: 10.1007/bf00581227] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The effect of a neutral amino acid, 2-aminoisobutyric acid (AIB) on steady state cell volume has been examined in rat renal papillary slices incubated in hyperosmotic media (2,000 mosmol/kg H2O) containing high concentrations of NaCl and urea (thus imitating papillary interstitial fluid in the intact kidney during antidiuresis). Volumes were significantly increased (P less than 0.001) when external AIB was raised from 0.1 to 10 mmol/l. Na+-dependent AIB uptake occurred, and there were net increases in cell contents of Na+ and Cl-. Replacement of Na+ by Li+, but not by other cations, did not influence the effect of AIB concentration on cell volume, but this was abolished when Cl- was replaced by other anions. The effect of AIB was abolished by diphenylamine-2-carboxylate (10(-3) mmol/l), bumetanide (at 1 mmol/l but not 10(-2) mmol/l) and by N,N'-dicyclohexylcarbodiimide (0.5 mmol/l), but not by amiloride (1 mmol/l) or 4-acetamido-4'-iso-thiocyanato-stilbene-2,2'-disulphonic acid (1 mmol/l), and was enhanced by the presence of Ba2+ or quinine (1 mmol/l). The findings are interpreted in terms of an inwardly-directed Na+-amino acid cotransporter, which determines steady-state volume, requires simultaneous entry of Cl- through conductive pathways, and whose effects on cell volume are moderated by K+ efflux through volume-sensitive K+ channels.
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Affiliation(s)
- R O Law
- Department of Physiology, University of Leicester, Great Britain
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Van Winkle LJ, Haghighat N, Campione AL, Gorman JM. Glycine transport in mouse eggs and preimplantation conceptuses. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 941:241-56. [PMID: 2454661 DOI: 10.1016/0005-2736(88)90185-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
At least two Na+-dependent systems for glycine transport became detectable, while another became undetectable during preimplantation development of mouse conceptuses. Glycine was taken up by a process in eggs and cleavage-stage conceptuses which closely resembles system Gly. Mediated transport at these stages was more rapid at higher Cl- concentrations, sigmoidally related to the exogenous Na+ concentration, and strongly inhibited by sarcosine but not by amino acids with larger side chains. Moreover, neither Li+ nor choline could substitute for Na+ in stimulating glycine transport. System Gly was the only mediated process detected for glycine uptake in unfertilized and fertilized eggs and two-cell conceptuses, but two, less conspicuous, sarcosine-resistant, Na+-dependent components of transport also appeared to be present in eight-cell conceptuses. One of the latter components seemed to remain relatively inconspicuous when conceptuses formed blastocysts, while system Gly became undetectable. In contrast, the other less conspicuous component in eight-cell conceptuses appeared to become the most conspicuous transport process in blastocysts. The latter process, previously designated system B0,+, was shown here also to interact strongly with a broad scope of zwitterionic and cationic amino acid structures. Moreover, transport of glycine via system B0,+ was more rapid at higher Cl- concentrations, and this Na+-dependent process as well as Na+-independent leucine uptake were inhibited by choline. Furthermore, Na+-dependent amino acid transport in two-cell conceptuses and blastocysts was inhibited by 1.0 or 10 mM ouabain, but the inhibition was incomplete at both concentrations. Since Na+/K+-ATPase has not been detected in two-cell conceptuses, inhibition of amino acid transport by ouabain may not have been due solely to an effect on this enzyme. The level of system Gly activity decreased during the development of eight-cell conceptuses from eggs, and this decrease could contribute to an associated decline in intracellular glycine. Since other amino acids begin to compete strongly with glycine for transport when system B0,+ replaces system Gly in conceptuses, this qualitative change in transport activity may help account for a further decrease in the glycine content of conceptuses, reported elsewhere to occur after they form blastocysts.
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Affiliation(s)
- L J Van Winkle
- Department of Biochemistry, Chicago College of Osteopathic Medicine, IL 60615
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