Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1985-4-15
pubmed:abstractText
Lucifer Yellow CH (LY) is an excellent probe for fluid-phase pinocytosis. It accumulates within the macrophage vacuolar system, is not degraded, and is not toxic at concentrations of 6.0 mg/ml. Its uptake is inhibited at 0 degree C. Thioglycollate-elicited mouse peritoneal macrophages were found to exhibit curvilinear uptake kinetics of LY. Upon addition of LY to the medium, there was a brief period of very rapid cellular accumulation of the dye (1,400 ng of LY/mg protein per h at 1 mg/ml LY). This rate of accumulation most closely approximates the rate of fluid influx by pinocytosis. Within 60 min, the rate of LY accumulation slowed to a steady-state rate of 250 ng/mg protein per h which then continued for up to 18 h. Pulse-chase experiments revealed that the reduced rate of accumulation under steady-state conditions was due to efflux of LY. Only 20% of LY taken into the cells was retained; the remainder was released back into the medium. Efflux has two components, rapid and slow; each can be characterized kinetically as a first-order reaction. The kinetics are similar to those described by Besterman et al. (Besterman, J. M., J. A. Airhart, R. C. Woodworth, and R. B. Low, 1981, J. Cell Biol. 91:716-727) who interpret fluid-phase pinocytosis as involving at least two compartments, one small, rapidly turning over compartment and another apparently larger one which fills and empties slowly. To search for processes that control intracellular fluid traffic, we studied pinocytosis after treatment of macrophages with horseradish peroxidase (HRP) or with the tumor promoter phorbol myristate acetate (PMA). HRP, often used as a marker for fluid-phase pinocytosis, was observed to stimulate the rate of LY accumulation in macrophages. PMA caused an immediate four- to sevenfold increase in the rate of LY accumulation. Both HRP and PMA increased LY accumulation by stimulating influx and reducing the percentage of internalized fluid that is rapidly recycled. A greater proportion of endocytosed fluid passes into the slowly emptying compartment (presumed lysosomes). These experiments demonstrate that because of the considerable efflux by cells, measurement of marker accumulation inaccurately estimates the rate of fluid pinocytosis. Moreover, pinocytic flow of water and solutes through cytoplasm is subject to regulation at points beyond the formation of pinosomes.
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-1030706, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-14907713, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-274729, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-332066, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-4347251, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-6156175, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-6196369, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-6298247, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-6304124, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-6853596, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-688392, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-6893202, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-7107699, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-7118995, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-7188905, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-7328118, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-7400219, http://linkedlifedata.com/resource/pubmed/commentcorrection/3972898-87515
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9525
pubmed:author
pubmed:issnType
Print
pubmed:volume
100
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
851-9
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Phorbol esters and horseradish peroxidase stimulate pinocytosis and redirect the flow of pinocytosed fluid in macrophages.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't