Linked Life Data

10737903

Source:http://linkedlifedata.com/resource/pubmed/id/10737903

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2000-4-24
pubmed:abstractText
IGF-I is mitogenic for the bovine mammary epithelial cell line MAC-T. In addition, IGF-I specifically upregulates IGFBP-3 synthesis in these cells. To investigate this effect on cell growth and IGF-I responsiveness, cell lines were developed that constitutively express IGFBP-3. MAC-T cells transfected with IGFBP-3 (+BP3) or vector alone (Mock) grew similarly over 7 days in 10 or 1% fetal calf serum. Basal DNA synthesis was lower (70%) in +BP3 cells compared to Mock cells. However, DNA synthesis was increased by IGF-I (1-50 ng/ml) relative to untreated controls to a greater extent in +BP3 cells compared to Mock cells. IGF-I (20 ng/ml) increased DNA synthesis 11- and threefold in +BP3 and Mock cells, respectively. Additionally, +BP3 cells were more sensitive to the lower concentrations of IGF-I (1-5 ng/ml). In contrast, preincubation of Mock cells with exogenous IGFBP-3 did not enhance responsiveness or sensitivity to IGF-I. Basal DNA synthesis was unaffected by either an IGF neutralizing antibody or exogenous IGFBP3, indicating the differences observed between +BP3 and Mock cells were not attributable to sequestration of endogenous IGF-I by IGFBP-3. There were no differences between +BP3 and Mock cells in IGF-I receptor number or affinity. DNA synthesis was also increased in +BP3 cells, compared to controls, in response to 5 microg/ml insulin and 2.5 ng/ml Long R(3)IGF-I, indicating that the potentiated response did not require an interaction with IGFBP-3. These results suggest that IGF-I regulation of IGFBP-3 represents a regulatory loop, the function of which is to increase IGF-I bioactivity, using a mechanism that does require an IGF-I-IGFBP-3 interaction.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9541
pubmed:author
pubmed:copyrightInfo
Copyright 2000 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:volume
183
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
273-83
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Insulin-like growth factor binding protein-3 mediates IGF-I action in a bovine mammary epithelial cell line independent of an IGF interaction.
pubmed:affiliation
Department of Nutritional Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901-8520, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't