Linked Life Data

10440937

Source:http://linkedlifedata.com/resource/pubmed/id/10440937

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1999-10-12
pubmed:abstractText
Thyroid hormones influence both bone formation and bone resorption. Clinical data and animal studies provide evidence of skeletal site heterogeneity (hip vs. spine) of bone responses to thyroid hormones. In vitro studies also demonstrate direct effects of thyroid hormones on cells of the osteoblast lineage. Transcriptional regulation by thyroid hormone is mediated by ligand-dependent transcription factors called thyroid hormone receptors (TRs). Two genes, c-ErbAalpha and c-ErbAbeta, generate at least four TR isoforms in the rat: TRalpha(1), c-erbAalpha(2), TRbeta(1), and TRbeta(2). Although functional TRs have been identified in cells of the osteoblast lineage, it is still not known if TR isoform expression in bone differs depending upon which skeletal site is examined. We have used ribonuclease protection assay and Northern blot analysis to simultaneously examine the expression of TR isoform mRNAs in adult rat femoral and vertebral bone. TRalpha(1), c-erbAalpha(2), and TRbeta(1) are expressed in both femur and vertebra whole bone. Bone marrow cells from both skeletal sites were also cultured under conditions whereby the osteoprogenitors differentiated into osteoblasts and formed a mineralized extracellular matrix. TRalpha(1), c-erbAalpha(2), and TRbeta(1) mRNAs are each expressed in both femoral and vertebral osteoblast cultures. The presence of TRalpha(1), c-erbAalpha(2), and beta(1) proteins was confirmed by Western analysis of nuclear protein extracts from femoral and vertebral cell cultures. These results indicate that the three predominant TR isoforms are highly expressed in bone and osteoblasts from femurs and vertebrae. Whether there are distinct mechanisms of thyroid hormone action mediated by TRalpha(1), c-erbAalpha(2), and TRbeta(1) at these separate skeletal sites remain to be shown.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0730-2312
pubmed:author
pubmed:copyrightInfo
Copyright 1999 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
74
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
684-93
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Expression of multiple thyroid hormone receptor isoforms in rat femoral and vertebral bone and in bone marrow osteogenic cultures.
pubmed:affiliation
Department of Orthopedics and Physical Rehabilitation, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.