Linked Life Data

8119139

Source:http://linkedlifedata.com/resource/pubmed/id/8119139

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1994-4-7
pubmed:abstractText
We previously found that the inhibition of bone formation and trabecular osteopenia induced by skeletal unloading in rats are associated with reduced proliferation of osteoblastic cells lining the bone surface. In this study, we examined the effects of insulin-like growth factor-I (IGF-I) on trabecular bone formation, bone mineral density, and proliferation of marrow-derived osteoblastic cells in unloaded rats. Skeletal unloading of hind limbs was induced by tail suspension, and recombinant human IGF-I was administered at two different doses (1.3 or 2.0 mg/kg.day) in control and unloaded rats by continuous infusion for 14 days. Treatment with IGF-I had no effect on plasma glucose levels, body weight, or longitudinal bone growth. The double calcein-labeled surface, bone formation rate, and trabecular number measured at the tibial metaphysis were lower in unloaded rats compared to controls and were increased after IGF-I treatment. The increased number of bone-forming sites induced by IGF-I was associated with partial prevention of trabecular bone loss in unloaded rats. In contrast to the beneficial effects of IGF-I on bone formation and bone mineral content in unloaded rats, IGF-I had no effect in control rats. To evaluate the cellular mechanisms of action of IGF-I, marrow stromal cells were derived from the tibia of unloaded and control rats and studied in vitro. Unloading was associated with a decreased proliferation of alkaline phosphatase-positive (ALP+) marrow stromal cells. Treatment with IGF-I increased the number of ALP+ cells in unloaded rats, but not in control rats. IGF-I treatment increased ALP activity and osteocalcin production by marrow-derived cells in suspended and control rats, suggesting that IGF-I stimulated the proliferation and differentiation of osteoblast precursor cells. These results indicate that IGF-I infusion enhanced the recruitment of osteoblastic cells, increased trabecular bone formation, and partially prevented trabecular bone loss in unloaded rats, which supports the hypothesis that IGF-I may mediate in part the effects of loading on bone formation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
134
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1031-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Insulin-like growth factor-I increases trabecular bone formation and osteoblastic cell proliferation in unloaded rats.
pubmed:affiliation
INSERM U-349, Paris, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't