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Effects of bicarbonate on lithium transport in human red cells
Lithium influx into human erythrocytes increased 12-fold, when chloride was replaced with bicarbonate in a 150 mM lithium medium (38 degrees C. pH 7.4). The increase was linearly related to both lithium- and bicarbonate concentration, and was completely eliminated by the amino reagent 4, 4'- di...
Formato: | Texto |
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Lenguaje: | English |
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The Rockefeller University Press
1978
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2215110/ https://www.ncbi.nlm.nih.gov/pubmed/670928 |
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collection | PubMed |
description | Lithium influx into human erythrocytes increased 12-fold, when chloride was replaced with bicarbonate in a 150 mM lithium medium (38 degrees C. pH 7.4). The increase was linearly related to both lithium- and bicarbonate concentration, and was completely eliminated by the amino reagent 4, 4'- diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). DIDS binds to an integral membrane protein (mol wt approximately 10(5) dalton) involved in anion exchange. Inhibition of both anion exchange and of bicarbonate-stimulated lithium influx was linearly related to DIDS binding. 1.1 X 10(6) DIDS molecules per cell caused complete inhibition of both processes. Both Cl- and Li+ can apparently be transported by the anion transport mechanism. The results support our previous proposal that bicarbonate-induced lithium permeability is due to transport of lithium-carbonate ion pairs (LiCO-3). DIDS-sensitive lithium influx had a high activation energy (24 kcal/mol), compatible with transport by the anion exchange mechanism. We have examined how variations of passive lithium permeability, induced by bicarbonate, affect the sodium-driven lithium counter-transport in human erythrocytes. The ability of the counter-transport system to establish a lithium gradient across the membrane decrease linearly with bicarbonate concentration in the medium. The counter-transport system was unaffected by DIDS treatement. At a plasma bicarbonate concentration of 24 mM, two-thirds of the lithium influx is mediated by the bicarbonate-stimulated pathway, and the fraction will increase significantly in metabolic alkalosis. |
format | Text |
id | pubmed-2215110 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1978 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-22151102008-04-23 Effects of bicarbonate on lithium transport in human red cells J Gen Physiol Articles Lithium influx into human erythrocytes increased 12-fold, when chloride was replaced with bicarbonate in a 150 mM lithium medium (38 degrees C. pH 7.4). The increase was linearly related to both lithium- and bicarbonate concentration, and was completely eliminated by the amino reagent 4, 4'- diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). DIDS binds to an integral membrane protein (mol wt approximately 10(5) dalton) involved in anion exchange. Inhibition of both anion exchange and of bicarbonate-stimulated lithium influx was linearly related to DIDS binding. 1.1 X 10(6) DIDS molecules per cell caused complete inhibition of both processes. Both Cl- and Li+ can apparently be transported by the anion transport mechanism. The results support our previous proposal that bicarbonate-induced lithium permeability is due to transport of lithium-carbonate ion pairs (LiCO-3). DIDS-sensitive lithium influx had a high activation energy (24 kcal/mol), compatible with transport by the anion exchange mechanism. We have examined how variations of passive lithium permeability, induced by bicarbonate, affect the sodium-driven lithium counter-transport in human erythrocytes. The ability of the counter-transport system to establish a lithium gradient across the membrane decrease linearly with bicarbonate concentration in the medium. The counter-transport system was unaffected by DIDS treatement. At a plasma bicarbonate concentration of 24 mM, two-thirds of the lithium influx is mediated by the bicarbonate-stimulated pathway, and the fraction will increase significantly in metabolic alkalosis. The Rockefeller University Press 1978-06-01 /pmc/articles/PMC2215110/ /pubmed/670928 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/). |
spellingShingle | Articles Effects of bicarbonate on lithium transport in human red cells |
title | Effects of bicarbonate on lithium transport in human red cells |
title_full | Effects of bicarbonate on lithium transport in human red cells |
title_fullStr | Effects of bicarbonate on lithium transport in human red cells |
title_full_unstemmed | Effects of bicarbonate on lithium transport in human red cells |
title_short | Effects of bicarbonate on lithium transport in human red cells |
title_sort | effects of bicarbonate on lithium transport in human red cells |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2215110/ https://www.ncbi.nlm.nih.gov/pubmed/670928 |