Linked Life Data

9164701

Source:http://linkedlifedata.com/resource/pubmed/id/9164701

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1997-7-15
pubmed:abstractText
The intestine is considered a major site for the breakdown and clearance of serum proteins. The mechanism of transport of macromolecules from the serosa into the lumen is unclear. The present study was designed to characterize the serosal to mucosal movement of albumin. Transport of bovine serum albumin (BSA) was assessed in short-circuited Ussing chambers, using stripped rat jejunum devoid of Peyer's patches. To define the kinetics of serosal to mucosal albumin transport the serosal surface was exposed to BSA at varying concentrations (0.5-5 mg.mL-1). Fluids from the mucosal compartment were sampled over time and assayed for immunologically intact BSA by ELISA. All subsequent experiments utilized a concentration of cold BSA (2 mg.mL-1) that produced maximal levels of intact BSA transport. To assess total BSA transport (intact BSA plus degraded BSA), 10 microCi (1 Ci = 37 GBq) 125I-labelled BSA was added to the serosal surface in addition to 2 mg.mL-1 cold BSA. To further characterize BSA transport tissues were treated with sodium fluoride (NaF) (metabolic inhibitor) or colchicine (an inhibitor of microtubule polymerization) or with the nerve blocker tetrodotoxin (TTX). All experiments using inhibitors were performed in paired tissues obtained from the same animal. Transport of intact BSA into the intestinal lumen was a saturable process, with a Vmax of 251 +/- 13 ng.cm-2.h-1 and a Km of 0.72 +/- 0.1 mg.mL-1, and represented 7% of the total BSA flux into the intestinal lumen. In the presence of NaF (2 x 10(-3) M), transport of both intact and total BSA was significantly inhibited (intact: control 374 +/- 80 vs. NaF 46 +/- 11, 88% inhibition; total: control 3288 +/- 296 vs. NaF 2550 +/- 235 ng.cm-2.h-1, 22% inhibition; p < 0.05). In addition, colchicine significantly inhibited intact BSA transport (control 339 +/- 15 vs. colchicine 206 +/- 13 ng.cm-2.h-1, 39% inhibition; p < 0.05). TTX had no effect on intact BSA flux. The findings suggest that transport of intact BSA from the serosa into the intestinal lumen is a saturable, energy-dependent process, which involves microtubules but is not under neural regulation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0008-4212
pubmed:author
pubmed:issnType
Print
pubmed:volume
75
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
193-8
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Transport of albumin into the intestinal lumen of the rat.
pubmed:affiliation
Gastrointestinal Research Group, University of Calgary, AB, Canada.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't