Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1993-3-2
pubmed:abstractText
We have previously demonstrated that population density alters the responsiveness of GH4C1 pituitary tumor cells to 17 beta-estradiol (E2). At a low population density E2 was observed to increase prolactin mRNA and stimulate cell proliferation, whereas this estrogen was unable to elicit these responses when the cells were maintained at a 4-fold higher population density. In an attempt to determine the mechanism through which population density alters responsiveness to E2, the steady-state level of estrogen receptor (ER), the affinity of ER for E2, and ER down-regulation have been examined in both intact and fractionated cells using ligand binding and ligand exchange assays. Data presented herein demonstrate that (1) GH4C1 cells maintained at low density expressed fewer ER than cells cultured at high density; (2) ER in cells cultured at high density displayed a reduced affinity for E2; (3) ER down-regulation occurring within 1 h of E2 addition appeared to be more pronounced in high density cultures; and (4) steady-state levels of ER were similar in low and high density cells treated with E2 for 1 through 5 days. Although none of these observations appear to correlate with the previously observed effects of population density on the responsiveness of GH4C1 cells to E2, they further illustrate the potential of the culture environment to alter the responsiveness to estrogenic stimuli by altering the properties of the ER.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0960-0760
pubmed:author
pubmed:issnType
Print
pubmed:volume
44
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
53-60
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Changes in population density elicit quantitative and qualitative changes in the estrogen receptor in intact GH4C1 pituitary tumor cells.
pubmed:affiliation
Eppley Institute for research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha 68198-6805.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't