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Insulin Stimulates Transepithelial Sodium Transport by Activation of a Protein Phosphatase That Increases Na-K Atpase Activity in Endometrial Epithelial Cells
The objective of this study was to investigate the effects of insulin and insulin-like growth factor I on transepithelial Na(+) transport across porcine glandular endometrial epithelial cells grown in primary culture. Insulin and insulin-like growth factor I acutely stimulated Na(+) transport two- t...
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Formato: | Texto |
Lenguaje: | English |
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The Rockefeller University Press
1999
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2229463/ https://www.ncbi.nlm.nih.gov/pubmed/10498674 |
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author | Deachapunya, Chatsri Palmer-Densmore, Melissa O'Grady, Scott M. |
author_facet | Deachapunya, Chatsri Palmer-Densmore, Melissa O'Grady, Scott M. |
author_sort | Deachapunya, Chatsri |
collection | PubMed |
description | The objective of this study was to investigate the effects of insulin and insulin-like growth factor I on transepithelial Na(+) transport across porcine glandular endometrial epithelial cells grown in primary culture. Insulin and insulin-like growth factor I acutely stimulated Na(+) transport two- to threefold by increasing Na(+)-K(+) ATPase transport activity and basolateral membrane K(+) conductance without increasing the apical membrane amiloride-sensitive Na(+) conductance. Long-term exposure to insulin for 4 d resulted in enhanced Na(+) absorption with a further increase in Na(+)-K(+) ATPase transport activity and an increase in apical membrane amiloride-sensitive Na(+) conductance. The effect of insulin on the Na(+)-K(+) ATPase was the result of an increase in V(max) for extracellular K(+) and intracellular Na(+), and an increase in affinity of the pump for Na(+). Immunohistochemical localization along with Western blot analysis of cultured porcine endometrial epithelial cells revealed the presence of α-1 and α-2 isoforms, but not the α-3 isoform of Na(+)-K(+) ATPase, which did not change in the presence of insulin. Insulin-stimulated Na(+) transport was inhibited by hydroxy-2-naphthalenylmethylphosphonic acid tris-acetoxymethyl ester [HNMPA-(AM)(3)], a specific inhibitor of insulin receptor tyrosine kinase activity, suggesting that the regulation of Na(+) transport by insulin involves receptor autophosphorylation. Pretreatment with wortmannin, a specific inhibitor of phosphatidylinositol 3–kinase as well as okadaic acid and calyculin A, inhibitors of protein phosphatase activity, also blocked the insulin-stimulated increase in short circuit and pump currents, suggesting that activation of phosphatidylinositol 3–kinase and subsequent stimulation of a protein phosphatase mediates the action of insulin on Na(+)-K(+) ATPase activation. |
format | Text |
id | pubmed-2229463 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1999 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-22294632008-04-21 Insulin Stimulates Transepithelial Sodium Transport by Activation of a Protein Phosphatase That Increases Na-K Atpase Activity in Endometrial Epithelial Cells Deachapunya, Chatsri Palmer-Densmore, Melissa O'Grady, Scott M. J Gen Physiol Original Article The objective of this study was to investigate the effects of insulin and insulin-like growth factor I on transepithelial Na(+) transport across porcine glandular endometrial epithelial cells grown in primary culture. Insulin and insulin-like growth factor I acutely stimulated Na(+) transport two- to threefold by increasing Na(+)-K(+) ATPase transport activity and basolateral membrane K(+) conductance without increasing the apical membrane amiloride-sensitive Na(+) conductance. Long-term exposure to insulin for 4 d resulted in enhanced Na(+) absorption with a further increase in Na(+)-K(+) ATPase transport activity and an increase in apical membrane amiloride-sensitive Na(+) conductance. The effect of insulin on the Na(+)-K(+) ATPase was the result of an increase in V(max) for extracellular K(+) and intracellular Na(+), and an increase in affinity of the pump for Na(+). Immunohistochemical localization along with Western blot analysis of cultured porcine endometrial epithelial cells revealed the presence of α-1 and α-2 isoforms, but not the α-3 isoform of Na(+)-K(+) ATPase, which did not change in the presence of insulin. Insulin-stimulated Na(+) transport was inhibited by hydroxy-2-naphthalenylmethylphosphonic acid tris-acetoxymethyl ester [HNMPA-(AM)(3)], a specific inhibitor of insulin receptor tyrosine kinase activity, suggesting that the regulation of Na(+) transport by insulin involves receptor autophosphorylation. Pretreatment with wortmannin, a specific inhibitor of phosphatidylinositol 3–kinase as well as okadaic acid and calyculin A, inhibitors of protein phosphatase activity, also blocked the insulin-stimulated increase in short circuit and pump currents, suggesting that activation of phosphatidylinositol 3–kinase and subsequent stimulation of a protein phosphatase mediates the action of insulin on Na(+)-K(+) ATPase activation. The Rockefeller University Press 1999-10-01 /pmc/articles/PMC2229463/ /pubmed/10498674 Text en © 1999 The Rockefeller University Press 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 | Original Article Deachapunya, Chatsri Palmer-Densmore, Melissa O'Grady, Scott M. Insulin Stimulates Transepithelial Sodium Transport by Activation of a Protein Phosphatase That Increases Na-K Atpase Activity in Endometrial Epithelial Cells |
title | Insulin Stimulates Transepithelial Sodium Transport by Activation of a Protein Phosphatase That Increases Na-K Atpase Activity in Endometrial Epithelial Cells |
title_full | Insulin Stimulates Transepithelial Sodium Transport by Activation of a Protein Phosphatase That Increases Na-K Atpase Activity in Endometrial Epithelial Cells |
title_fullStr | Insulin Stimulates Transepithelial Sodium Transport by Activation of a Protein Phosphatase That Increases Na-K Atpase Activity in Endometrial Epithelial Cells |
title_full_unstemmed | Insulin Stimulates Transepithelial Sodium Transport by Activation of a Protein Phosphatase That Increases Na-K Atpase Activity in Endometrial Epithelial Cells |
title_short | Insulin Stimulates Transepithelial Sodium Transport by Activation of a Protein Phosphatase That Increases Na-K Atpase Activity in Endometrial Epithelial Cells |
title_sort | insulin stimulates transepithelial sodium transport by activation of a protein phosphatase that increases na-k atpase activity in endometrial epithelial cells |
topic | Original Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2229463/ https://www.ncbi.nlm.nih.gov/pubmed/10498674 |
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