Alanine transport in rat liver plasma membrane vesicles during the acute-phase response in young and old rats

1995 ◽  
Vol 77 (3) ◽  
pp. 159-168 ◽  
Author(s):  
Maria Giovanna Leonardi ◽  
Roberto Comolli
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Acute Phase ◽  
Acute Phase Response ◽  
Membrane Vesicles ◽  
Phase Response ◽  
Plasma Membrane Vesicles ◽  
Liver Plasma Membrane ◽  
Alanine Transport ◽  
Old Rats

scholarly journals Sensitivity of system A and ASC transport activities to thiol-group-modifying reagents in rat liver plasma-membrane vesicles. Evidence for a direct binding of N-ethylmaleimide and iodoacetamide on A and ASC carriers

1990 ◽  
Vol 271 (2) ◽  
pp. 297-303 ◽  
Author(s):  
E Pola ◽  
J Bertran ◽  
A Roca ◽  
M Palacín ◽  
A Zorzano ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Amino Acid ◽  
Rat Liver ◽  
Membrane Vesicles ◽  
Thiol Group ◽  
Transport Activity ◽  
Plasma Membrane Vesicles ◽  
Liver Plasma Membrane ◽  
System A ◽  
Alanine Transport

1. In the present study we have examined the sensitivity of A and ASC amino-acid-carrier activities in rat liver plasma-membrane vesicles to the thiol-group modifying reagents N-ethylmaleimide (NEM) and iodoacetamide (IA). To this end, the different Na(+)-dependent entities involved in alanine transport were assessed. 2. NEM inactivated Na(+)-dependent alanine transport as a result of the inhibition of both system A and ASC transport activities. The functional sensitivity of system A to NEM was greater than that of system ASC. 3. The presence of L-alanine (10 mM) during the exposure of vesicles to NEM afforded partial protection to system A, but not to the ASC, carrier. This effect was specific, since the presence of L-phenylalanine (10 mM) did not cause any protection. 4. Na+ did not protect A or ASC carriers against NEM inactivation; however, the presence of Na+ (100 mM-NaCl) and L-alanine (10 mM) during the exposure of the vesicles to NEM protected against inactivation of system A and ASC transport activities. The extent of protection was greater in the case of the system ASC transport activity than in the case of the A carrier. 5. IA also diminished Na(+)-dependent alanine transport by inhibition of A and ASC transport activities. Sodium and L-alanine afforded protection to both A and ASC transport activities from the inhibitory action of IA. The extent of protection induced by substrates was similar for both carriers. 6. It is concluded that there is one, or several, free thiol groups in A and ASC carriers, the integrity of which is essential for transport activity. Sensitivity to thiol-group-specific reagents and the pattern of protection with substrates against inactivation is different in A and ASC carriers. That suggests the existence of topological dissimilarities regarding the thiol-group containing site(s) in A and ASC amino acid carriers.

Thiamine transport by basolateral rat liver plasma membrane vesicles

1992 ◽  
Vol 103 (3) ◽  
pp. 1056-1065 ◽  
Author(s):  
Richard H. Moseley ◽  
Pankaj G. Vashi ◽  
Suzanne M. Jarose ◽  
Chris J. Dickinson ◽  
Patricia A. Permoad
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Liver Plasma Membrane ◽  
Thiamine Transport

scholarly journals Evidence for carrier-mediated chloride/bicarbonate exchange in canalicular rat liver plasma membrane vesicles.

1985 ◽  
Vol 75 (4) ◽  
pp. 1256-1263 ◽  
Author(s):  
P J Meier ◽  
R Knickelbein ◽  
R H Moseley ◽  
J W Dobbins ◽  
J L Boyer
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Liver Plasma Membrane

Multispecific anion exchange in basolateral (sinusoidal) rat liver plasma membrane vesicles

1986 ◽  
Vol 251 (5) ◽  
pp. G656-G664 ◽  
Author(s):  
G. Hugentobler ◽  
P. J. Meier
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Driving Forces ◽  
Competitive Inhibition ◽  
Membrane Vesicles ◽  
Ph Gradient ◽  
Disulfonic Acid ◽  
Sulfate Uptake ◽  
Plasma Membrane Vesicles ◽  
Liver Plasma Membrane

The mechanisms and driving forces for hepatic uptake of sulfate were investigated in basolateral (sinusoidal) rat liver plasma membrane vesicles. A transmembrane pH difference (pH 8.0 inside, 6.0 outside) stimulated sulfate uptake above equilibrium (“overshoot”). This pH gradient-stimulated sulfate uptake was saturable with increasing concentrations of sulfate and could be inhibited by probenecid, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), carbonyl cyanide p-(trifluoromethoxy)-phenylhydrazone, and nigericin. At low buffer concentrations and pH 6.0 an inwardly directed sodium gradient also stimulated sulfate uptake. This sodium-dependent sulfate uptake could be inhibited by amiloride and DIDS, indicating indirect coupling of sodium and sulfate flux through concomitant sodium-proton and sulfate-hydroxyl exchange. Cisinhibition of initial pH gradient-stimulated sulfate uptake, as well as transstimulation of sulfate uptake under pH-equilibrated conditions (pH 7.5 inside and outside), were observed with sulfate, thiosulfate, oxalate, and succinate, but not with chloride, bicarbonate, acetate, lactate, pyruvate, p-aminohippurate, citrate, glutamate, aspartate, and taurocholate. Furthermore, cholate and sulfobromophthalein exhibited competitive inhibition of pH gradient-stimulated sulfate uptake. In addition, an inside-to-outside hydroxyl gradient also stimulated uptake of cholate and this pH gradient-sensitive portion of cholate uptake was inhibited by extravesicular sulfate. In contrast to basolateral membranes, no evidence for multispecific sulfate-hydroxyl exchange was found in canalicular plasma membrane vesicles.

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