Linked Life Data

2114019

Source:http://linkedlifedata.com/resource/pubmed/id/2114019

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1990-8-8
pubmed:abstractText
Transport of 14C-labeled acetic, propionic (PA), butyric, valeric, heptanoic (HA), and octanoic (OA) acids across the Madin Darby canine kidney (MDCK) epithelial cell monolayer grown on a porous polycarbonate membrane was studied in Hanks' balanced salt solution (HBSS) at 37 degrees C in both apical-to-basolateral and basolateral-to-apical directions. At micromolar concentrations of solutes, metabolic decomposition was significant as evidenced by [14C]CO2 production during the OA transport. The apparent permeability (Pe) indicates that as lipophilicity increases, diffusion across the "unstirred" boundary layer becomes rate limiting. In support of this notion, transport of OA and HA was enhanced by agitation, showed an activation energy of 3.7 kcal/mol for OA, and resulted in identical Pe values for both transport directions. Analysis of Pe changes with varying alkyl chain length resulted in a delta G of -0.68 +/- 0.09 kcal/mol for -CH2-group transfer from an aqueous phase to the MDCK cells. When the intercellular tight junctions were opened by the divalent chelator EGTA in Ca2+/Mg2(+)-free HBSS, transport of the fluid-phase marker Lucifer yellow greatly increased because of paracellular leakage. PA transport also showed a significant increase, but OA transport was independent of EGTA. Although albumin also undergoes paracellular transport in the presence of EGTA and OA binds strongly to albumin, OA transport in EGTA solution was unchanged by albumin. These observations indicate that transmembrane transport is the major mechanism for lipophilic substances. The present study, together with earlier work on the transport of polar substances, shows that the MDCK cell monolayer is an excellent model of the transepithelial transport barrier.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0724-8741
pubmed:author
pubmed:issnType
Print
pubmed:volume
7
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
325-31
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Transepithelial transport of aliphatic carboxylic acids studied in Madin Darby canine kidney (MDCK) cell monolayers.
pubmed:affiliation
Drug Delivery Systems Research, Upjohn Company, Kalamazoo, Michigan 49001.
pubmed:publicationType
Journal Article