Linked Life Data

1733295

Source:http://linkedlifedata.com/resource/pubmed/id/1733295

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1 Pt 2
pubmed:dateCreated
1992-2-25
pubmed:abstractText
Ionic NH+4 transport is an important mode of ammonia transport in the proximal convoluted tubule (PCT). NH+4 transport via the Na-H exchanger has been previously demonstrated. Potassium channels are present in the proximal tubule, but their role in ammonia transport has not been evaluated. We studied rat PCTs perfused in situ at 30 nl/min with solutions containing 5 mM HCO3; ammonia was measured with a fluorometric method. When perfused with the potent amiloride analogue 5-(N-ethyl-N-isopropyl)-amiloride (EIPA, 500 microM) or with BaCl2 (10 mM), ammonia entry (14.3 +/- 1.7 and 11.8 +/- 1.5 pmol.min-1.mm-1, respectively) was unaffected compared with control (12.8 +/- 1.0 pmol.min-1.mm-1). However, the combination of EIPA and barium inhibited entry (7.4 +/- 1.0 pmol.min-1.mm-1, P less than 0.02 vs. other groups). Also, when perfused with 10 mM ammonia, neither EIPA nor BaCl alone blocked ammonia loss (70.5 +/- 9.1 and 60.5 +/- 5.9 pmol.min-1.mm-1, respectively) compared with control (53.4 +/- 6.0 pmol.min-1.mm-1). However, the combination inhibited ammonia loss (29.2 +/- 6.3 pmol.min-1.mm-1, P less than 0.025 vs. other groups). Thus blocking both the Na-H exchanger and potassium channels decreases PCT ammonia transport. As the combination was required, this implies that multiple pathways exist for NH+4 transport in the PCT. This is the first demonstration that a mode of NH+4 transport other than via the Na-H exchanger is important in this segment, and the data are most consistent with transport of ammonia via potassium channels.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
262
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
F36-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Effects of barium and 5-(N-ethyl-N-isopropyl)-amiloride on proximal tubule ammonia transport.
pubmed:affiliation
Department of Medicine, Jewish Hospital of St. Louis, Washington University, St. Louis, Missouri 63110.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't