Inhibition of system a amino acid transport activity by ethanol in bewo choriocarcinoma cells

2002 ◽  
Vol 187 (1) ◽  
pp. 209-216 ◽  
Author(s):  
Chandra R. Jones ◽  
Sonne R. Srinivas ◽  
Lawrence D. Devoe ◽  
Vadivel Ganapathy ◽  
Puttur D. Prasad
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Acid Transport ◽  
Transport Activity ◽  
System A ◽  
Choriocarcinoma Cells

scholarly journals A rapid method for the functional reconstitution of amino acid transport systems from rat liver plasma membranes. Partial purification of System A

1988 ◽  
Vol 255 (3) ◽  
pp. 963-969 ◽  
Author(s):  
A R Quesada ◽  
J D McGivan
Keyword(s):  
Amino Acid ◽  
Rapid Method ◽  
Amino Acid Transport ◽  
Plasma Membranes ◽  
Transport Systems ◽  
Partial Purification ◽  
Acid Transport ◽  
Transport Activity ◽  
System A ◽  
System L

A rapid method for the functional reconstruction of amino acid transport from liver plasma-membrane vesicles using the neutral detergent decanoyl-N-glucamide (‘MEGA-10’) is described. The method is a modification of that previously employed in this laboratory for reconstitution of amino acid transport systems from kidney brush-border membranes [Lynch & McGivan (1987) Biochem. J. 244, 503-508]. The transport activities termed ‘System A’, ‘System N’, and ‘System L’ are all reconstituted. The reconstitution procedure is rapid and efficient and is suitable as an assay for transport activity in studies involving membrane fractionation. By using this reconstitution procedure, System A transport activity was partially purified by lectin-affinity chromatography.

scholarly journals Electrogenic Na+-dependentl-alanine transport in the lizard duodenum. Involvement of systems A and ASC

2001 ◽  
Vol 280 (3) ◽  
pp. R612-R622
Author(s):  
Virtudes Medina ◽  
Antonio Lorenzo ◽  
Mario Dı́az
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Short Circuit ◽  
Duodenal Mucosa ◽  
Neutral Amino Acid ◽  
Acid Transport ◽  
Transport Activity ◽  
System A ◽  
Alanine Transport ◽  
Gallotia Galloti

l-Alanine transport across the isolated duodenal mucosa of the lizard Gallotia galloti has been studied in Ussing chambers under short-circuit conditions. Net l-alanine fluxes, transepithelial potential difference (PD), and short-circuit current ( Isc) showed concentration-dependent relationships. Na+-dependent l-alanine transport was substantially inhibited by the analog α-methyl aminoisobutyric acid (MeAIB). Likewise, MeAIB fluxes were completely inhibited byl-alanine, indicating the presence of system A for neutral amino acid transport. System A transport activity was electrogenic and exhibited hyperbolic relationships for net MeAIB fluxes, PD, and Isc, which displayed similar apparent K m values. Na+-dependentl-alanine transport, but not MeAIB transport, was partially inhibited by l-serine and l-cysteine, indicating the participation of system ASC. This transport activity represents the major pathway for l-alanine absorption and seemed to operate in an electroneutral mode with a negligible contribution to the l-alanine-induced electrogenicity. It is concluded from the present study that the active Na+-dependent l-alanine transport across the isolated duodenal mucosa of Gallotia galloti results from the independent activity of systems A and ASC for neutral amino acid transport.

scholarly journals Leptin Affects System A Amino Acid Transport Activity in the Human Placenta: Evidence for STAT3 Dependent Mechanisms

Placenta ◽  
2009 ◽  
Vol 30 (4) ◽  
pp. 361-367 ◽  
Author(s):  
F. von Versen-Höynck ◽  
A. Rajakumar ◽  
M.S. Parrott ◽  
R.W. Powers
Keyword(s):  
Amino Acid ◽  
Human Placenta ◽  
Amino Acid Transport ◽  
Acid Transport ◽  
Transport Activity ◽  
System A

scholarly journals Effect of high altitude on human placental amino acid transport

2020 ◽  
Vol 128 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Owen. R. Vaughan ◽  
Fredrick Thompson ◽  
Ramón. A. Lorca ◽  
Colleen G. Julian ◽  
Theresa L. Powell ◽  
...  
Keyword(s):  
Birth Weight ◽  
Amino Acid ◽  
High Altitude ◽  
Sea Level ◽  
Amino Acid Transport ◽  
Acid Uptake ◽  
Acid Transport ◽  
Transport Capacity ◽  
System A ◽  
Low Altitude

Women residing at high altitudes deliver infants of lower birth weight than at sea level. Birth weight correlates with placental system A-mediated amino acid transport capacity, and severe environmental hypoxia reduces system A activity in isolated trophoblast and the mouse placenta. However, the effect of high altitude on human placental amino acid transport remains unknown. We hypothesized that microvillous membrane (MVM) system A and system L amino acid transporter activity is lower in placentas of women living at high altitude compared with low-altitude controls. Placentas were collected at term from healthy pregnant women residing at high altitude (HA; >2,500 m; n = 14) or low altitude (LA; <1,700 m; n = 14) following planned, unlabored cesarean section. Birth weight, but not placenta weight, was 13% lower in HA pregnancies (2.88 ± 0.11 kg) compared with LA (3.30 ± 0.07 kg, P < 0.01). MVM erythropoietin receptor abundance, determined by immunoblot, was greater in HA than in LA placentas, consistent with lower placental oxygen levels at HA. However, there was no effect of altitude on MVM system A or L activity, determined by Na+-dependent [14C]methylaminoisobutyric acid uptake and [3H]leucine uptake, respectively. MVM abundance of glucose transporters (GLUTs) 1 and 4 and basal membrane GLUT4 were also similar in LA and HA placentas. Low birth weights in the neonates of women residing at high altitude are not a consequence of reduced placental amino acid transport capacity. These observations are in general agreement with studies of IUGR babies at low altitude, in which MVM system A activity is downregulated only in growth-restricted babies with significant compromise. NEW & NOTEWORTHY Babies born at high altitude are smaller than at sea level. Birth weight is dependent on growth in utero and, in turn, placental nutrient transport. We determined amino acid transport capacity in placentas collected from women resident at low and high altitude. Altitude did not affect system A amino acid transport across the syncytiotrophoblast microvillous membrane, suggesting that impaired placental amino acid transport does not contribute to reduced birth weight in this high-altitude population.

Ceramide down‐regulates System A amino acid transport and protein synthesis in rat skeletal muscle cells

2004 ◽  
Vol 19 (3) ◽  
pp. 1-24 ◽  
Author(s):  
Russell Hyde ◽  
Eric Hajduch ◽  
Darren J. Powell ◽  
Peter M. Taylor ◽  
Harinder S. Hundal
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Acid Transport ◽  
Rat Skeletal Muscle ◽  
System A
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