AJP - Endo Track the topics, authors and articles important to you
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Endocrinol Metab 275: E222-E228, 1998;
0193-1849/98 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Gabbitas, B.
Right arrow Articles by Canalis, E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Gabbitas, B.
Right arrow Articles by Canalis, E.
Vol. 275, Issue 2, E222-E228, August 1998

Insulin-like growth factors sustain insulin-like growth factor-binding protein-5 expression in osteoblasts

Bari Gabbitas1 and Ernesto Canalis1,2

1 Departments of Research and Medicine, Saint Francis Hospital and Medical Center, Hartford 06105; and 2 The University of Connecticut School of Medicine, Farmington, Connecticut 06030

Insulin-like growth factors (IGFs) I and II are considered to be autocrine regulators of bone cell function. Recently, we demonstrated that IGF-I induces IGF-binding protein-5 (IGFBP-5) expression in cultures of osteoblast-enriched cells from 22-day fetal rat calvariae (Ob cells). In the present study, we postulated that IGFs play an autocrine role in the maintenance of IGFBP-5 basal expression in Ob cells. IGFBP-2 and -3, at concentrations that bind endogenous IGFs, decreased IGFBP-5 mRNA levels, as determined by Northern blot analysis, and protein levels, as determined by Western immunoblots of extracellular matrix extracts of Ob cells. IGFBP-2 and -3 in excess inhibited IGFBP-5 heterogeneous nuclear RNA levels, as determined by RT-PCR, and did not alter the half-life of IGFBP-5 mRNA in transcriptionally arrested Ob cells. In conclusion, blocking endogenous IGFs in Ob cells represses IGFBP-5 expression, suggesting that IGFs are autocrine inducers of IGFBP-5 synthesis in osteoblasts.

skeletal tissue; extracellular matrix; bone formation; transcription


This article has been cited by other articles:


Home page
 J. Biol. Chem.Home page
S. Gutierrez, A. Javed, D. K. Tennant, M. van Rees, M. Montecino, G. S. Stein, J. L. Stein, and J. B. Lian
CCAAT/Enhancer-binding Proteins (C/EBP) beta and delta Activate Osteocalcin Gene Transcription and Synergize with Runx2 at the C/EBP Element to Regulate Bone-specific Expression
J. Biol. Chem., January 4, 2002; 277(2): 1316 - 1323.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online