Dehydroascorbate and ascorbate transport in rat liver microsomal vesicles

Gábor Bánhegyi, Paola Marcolongo, Ferenc Puskás, Rosella Fulceri, József Mandl, Angelo Benedetti

Research output: Contribution to journalArticle

71 Citations (Scopus)

Abstract

Ascorbate and dehydroascorbate transport was investigated in rat liver microsomal vesicles using radiolabeled compounds and a rapid filtration method. The uptake of both compounds was time- and temperature dependent, and saturable. Ascorbate uptake did not reach complete equilibrium, it had low affinity and high capacity. Ascorbate influx could not be inhibited by glucose, dehydroascorbate, or glucose transport inhibitors (phloretin, cytochalasin B) but it was reduced by the anion transport inhibitor 4,4'- diisothiocyanostilbene-2,2'-disulfonic acid and by the alkylating agent N- ethylmaleimide. Ascorbate uptake could be stimulated by ferric iron and could be diminished by reducing agents (dithiothreitol, reduced glutathione). In contrast, dehydroascorbate uptake exceeded the level of passive equilibrium, it had high affinity and low capacity. Glucose cis inhibited and trans stimulated the uptake. Glucose transport inhibitors were also effective. The presence of intravesicular reducing compounds increased, while extravesicular reducing environment decreased dehydroascorbate influx. Our results suggest that dehydroascorbate transport is preferred in hepatic endoplasmic reticulum and it is mediated by a GLUT-type transporter. The intravesicular reduction of dehydroascorbate leads to the accumulation of ascorbate and contributes to the low intraluminal reduced/oxidized glutathione ratio.

Original languageEnglish
Pages (from-to)2758-2762
Number of pages5
JournalJournal of Biological Chemistry
Volume273
Issue number5
DOIs
Publication statusPublished - Jan 30 1998

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Liver
Rats
Glucose
Glutathione
Phloretin
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
Cytochalasin B
Ethylmaleimide
Glutathione Disulfide
Dithiothreitol
Alkylating Agents
Reducing Agents
Endoplasmic Reticulum
Anions
Iron
Temperature

ASJC Scopus subject areas

  • Biochemistry

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Dehydroascorbate and ascorbate transport in rat liver microsomal vesicles. / Bánhegyi, Gábor; Marcolongo, Paola; Puskás, Ferenc; Fulceri, Rosella; Mandl, József; Benedetti, Angelo.

In: Journal of Biological Chemistry, Vol. 273, No. 5, 30.01.1998, p. 2758-2762.

Research output: Contribution to journalArticle

Bánhegyi, Gábor ; Marcolongo, Paola ; Puskás, Ferenc ; Fulceri, Rosella ; Mandl, József ; Benedetti, Angelo. / Dehydroascorbate and ascorbate transport in rat liver microsomal vesicles. In: Journal of Biological Chemistry. 1998 ; Vol. 273, No. 5. pp. 2758-2762.
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