Linked Life Data

6300103

Source:http://linkedlifedata.com/resource/pubmed/id/6300103

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1983-5-27
pubmed:abstractText
Epidermal growth factor (EGF) increases Na+ uptake in several cell types through an electroneutral, amiloride-sensitive pathway putatively identified as Na+/H+ countertransport. The inferred cytosolic alkalinization resulting from this process has been proposed to be an important component of mitogenic stimulation. We studied the effect of EGF on the Na+/H+ exchange system of A431 cells, a cell line having a very high EGF receptor density but which is not mitogenically stimulated by EGF. We demonstrate that EGF rapidly activates net Na+ influx in A431 cells. Amiloride inhibits the EGF-dependent Na+ uptake (65% inhibition at 3 mM, ID50 approximately 0.3 mM) and inhibits much less the EGF-independent uptake. EGF is known to enhance 45Ca+ accumulation in A431 cells (Sawyer, S. T., and Cohen, S. (1981) Biochemistry 20, 6280-6286). The following findings indicate that EGF-dependent 22Na+ and 45Ca2+ uptake are two independent processes. 1) EGF effectively stimulates an amiloride-sensitive 22Na+ uptake in the absence of external Ca2+. 2) EGF-dependent 45Ca2+ uptake is not inhibited by amiloride. A new fluorescence technique is described for intracellular pH determination based on the introduction of fluorescein-labeled dextran into the cell cytoplasm. Using this method, the presence of amiloride-sensitive Na+/H+ exchange in A431 cells is documented. Although the lack of pH sensitivity of fluorescein fluorescence above pH 7.3-7.4 prevents a direct assessment of an EGF-induced increase of intracellular pH, the combined results of 22Na+ flux and intracellular pH measurements suggest that EGF activates Na+/H+ exchange in A431 cells. We conclude that enhanced Na+/H+ exchange may not necessarily be coupled to mitogenic triggering in different cell types, although the stimulation of Na+/H+ exchange may constitute a primary event in the mechanism of EGF action.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4883-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Epidermal growth factor stimulates amiloride-sensitive 22Na+ uptake in A431 cells. Evidence for Na+/H+ exchange.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't