Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1999-11-9
pubmed:abstractText
In perfused rat liver, there is phloretin-inhibitable urea efflux, but whether it is mediated by the kidney UT-A urea transporter family is unknown. To determine whether cultured HepG2 cells transport urea, thiourea influx was measured. HepG2 cells had a thiourea influx rate of 1739 +/- 156 nmol/g protein per min; influx was inhibited 46% by phloretin and 32% by thionicotinamide. Western analysis of HepG2 cell lysate using an antibody to UT-A1, UT-A2, and UT-A4 revealed two protein bands: 49 and 36 kD. The same bands were detected in cultured rat hepatocytes, freshly isolated rat hepatocytes, and in liver from rat, mouse, and chimpanzee. Both bands were present when analyzed by native gel electrophoresis, and deglycosylation of rat liver lysate had no effect on either band. Differential centrifugation of rat liver lysate showed that the 49-kD protein is in the membrane fraction and the 36-kD protein is in the cytoplasm. To determine whether the abundance of these UT-A proteins varies in vivo, rats were made uremic by 5/6 nephrectomy. The 49-kD protein was significantly increased 5.5-fold in livers from uremic rats compared to pair-fed control rats. It is concluded that phloretin-inhibitable urea flux in liver may occur via a 49-kD protein that is specifically detected by a UT-A antibody. Uremia increases the abundance of this 49-kD UT-A protein in rat liver in vivo.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1046-6673
pubmed:author
pubmed:issnType
Print
pubmed:volume
10
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2076-83
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:10505683-Animals, pubmed-meshheading:10505683-Biological Transport, pubmed-meshheading:10505683-Blotting, Western, pubmed-meshheading:10505683-Carrier Proteins, pubmed-meshheading:10505683-Cells, Cultured, pubmed-meshheading:10505683-Disease Models, Animal, pubmed-meshheading:10505683-Liver, pubmed-meshheading:10505683-Male, pubmed-meshheading:10505683-Membrane Glycoproteins, pubmed-meshheading:10505683-Membrane Transport Proteins, pubmed-meshheading:10505683-Mice, pubmed-meshheading:10505683-Nephrectomy, pubmed-meshheading:10505683-Rats, pubmed-meshheading:10505683-Rats, Sprague-Dawley, pubmed-meshheading:10505683-Reference Values, pubmed-meshheading:10505683-Sensitivity and Specificity, pubmed-meshheading:10505683-Thiourea, pubmed-meshheading:10505683-Up-Regulation, pubmed-meshheading:10505683-Uremia
pubmed:year
1999
pubmed:articleTitle
UT-A urea transporter protein expressed in liver: upregulation by uremia.
pubmed:affiliation
Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S.