Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1993-8-24
pubmed:abstractText
The time course for development of polarized function and morphological distribution of pH regulatory mechanisms has been examined in a mouse mammary epithelial cell line (31EG4). Monolayers grown on permeable supports had tight junctions when grown 3-4 days in the presence of the lactogenic hormones dexamethasone (D, a synthetic glucocorticoid) and insulin (I), or in D, I, and prolactin (P), but there were no tight junctions in the absence of D. Microspectrofluorimetry of the pH-sensitive dye BCECF was used to measure pH (pHi) in cells mounted in a two-sided perfusion chamber to distinguish pH regulatory activity at the apical and basolateral membranes. Na/H exchange was assayed as the Na-dependent, amiloride-sensitive component of pHi recovery from an acid load induced by a pulse of NH3/NH4-containing solution. When monolayers were grown 3-4 d in the presence of P, D, and I, Na/H exchange was restricted to the basolateral membrane. In contrast, in the absence of P, Na/H exchange was present on both the apical and basolateral membranes. After 5-6 days, in the presence or absence of P, Na/H exchange was present only on the basolateral membrane. An antibody to the NHE-1 isoform of the Na/H exchanger was used to determine its morphological distribution. In all hormone conditions the antibody recognized a protein of approximately 110 kD (Western blot), and confocal immunofluorescence microscopy of this antibody and of an anti-ZO-1 (the marker of the tight junctions) antibody showed that the morphological distribution of the Na/H exchanger was similar to the functional distribution under all hormonal treatments. In addition, a putative Na/HCO3 cotransport system was monitored as a Na-dependent, amiloride-insensitive pHi recovery mechanisms that was inhibited by 200 microM H2DIDS. After treatment with D+I (but not with I alone) cotransport appeared exclusively on the basolateral membrane, and the polarized expression of this transporter was not altered by P. We conclude that when mammary cells are grown in D+I-containing media, the Na/H exchanger is expressed initially (i.e., after 3-4 d) on both the apical and basolateral membranes and later (5-6 d) on only the basolateral membrane. P (in the presence of D+I) selectively speeds this polarization, which is determined by polarized distribution of the exchanger to the apical and/or basal membrane and not by the activation and/or inactivation of transporters.(ABSTRACT TRUNCATED AT 400 WORDS)
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-12472, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-1374392, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-1409603, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-1649309, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-1649993, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-1651659, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-1658934, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-1662907, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-1712287, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-1847929, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-1849362, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-1850200, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-1858851, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2074799, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2083087, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2154036, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2156814, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2164778, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2172967, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2173416, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2174171, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2196994, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2465690, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2536298, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2549077, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2550651, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2556940, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2557022, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2653204, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2672330, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2835362, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2843567, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-284373, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2854165, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2893294, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-2901105, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-3136662, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-3528172, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-36128, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-3687435, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-388439, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-3939606, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-6815204, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-6833996, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-6833997, http://linkedlifedata.com/resource/pubmed/commentcorrection/8393012-942389
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9525
pubmed:author
pubmed:issnType
Print
pubmed:volume
122
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
589-600
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
More...