Linked Life Data

1550234

Source:http://linkedlifedata.com/resource/pubmed/id/1550234

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3 Pt 1
pubmed:dateCreated
1992-4-23
pubmed:abstractText
Taurine is an amino sulfonic acid maintained at relatively high concentrations in skate (Raja erinacea) hepatocytes (65 mmol/l intracellular water). To identify the transport mechanisms involved in intracellular taurine accumulation, uptake and efflux of [14C]taurine was measured in freshly isolated skate hepatocytes. Uptake of 50 microM taurine at 15 degrees C was essentially linear over 3 h when measured in normal elasmobranch Ringer, was diminished by replacement of extracellular Cl- with NO3-, and was almost completely abolished by replacement of Na+ with choline+ or K+. Kinetic studies suggested the presence of two saturable Na(+)-dependent taurine uptake systems [apparent taurine Michaelis constant = 0.089 +/- 0.028 and 4.47 +/- 0.49 mM and maximal velocity (Vmax) = 0.19 +/- 0.07 and 1.65 +/- 0.42 (SE) nmol.microliter-1.15 min-1 for high- and low-affinity components, respectively; n = 4], as well as a small contribution from an Na(+)-independent uptake system. Uptake was inhibited by other beta-amino acids but not by alpha-amino acids, taurocholate, or 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (0.5 mM). In contrast to uptake, efflux of [14C]taurine was relatively slow (approximately 10% in 2 h) and was unaffected by isosmotic replacement of extracellular Na+ with choline+ or K+ or by replacing Cl- with NO3-. These findings suggest distinct mechanisms for taurine uptake and efflux in skate hepatocytes; uptake is largely Na+ dependent and requires Cl- for maximal activity, whereas the efflux pathway is independent of transmembrane Na+, K+, or Cl- gradients. Maintenance of high intracellular taurine levels in skate hepatocytes is achieved by active Na(+)-dependent uptake processes and a relatively slow efflux.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
262
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
G445-50
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Taurine transport in skate hepatocytes. I. Uptake and efflux.
pubmed:affiliation
Department of Biophysics, University of Rochester School of Medicine, New York 14642.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.