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An IGF binding protein is an inhibitor of FGF stimulation

Authors :
J, Villaudy
J, Delbé
C, Blat
G, Desauty
A, Golde
L, Harel
Source :
Journal of cellular physiology. 149(3)
Publication Year :
1991

Abstract

We purified to homogeneity a growth inhibiting diffusible factor (IDF45) secreted by dense cultures of mouse 3T3 cells and which was able to inhibit 100% of DNA synthesis stimulated by serum in chick embryo fibroblasts (CEF) (Blat et al., 1989a). We then demonstrated that this factor was an IGF-binding protein (Blat et al., 1989b). Indeed, its N-terminal amino acid sequence was homologous to that of rat IGFBP-3. Our present results show that basic fibroblast growth factor (bFGF) induced, respectively, a fivefold and threefold increase in DNA synthesis in mouse embryo fibroblasts (MEF) and CEF. IDF-45 inhibited the stimulation induced by bFGF by about 65%, while stimulation induced by insulin, PDGF, or EGF was only weakly or not at all inhibited by IDF45. When bFGF stimulation was determined in the presence of a high concentration of insulin in conditions which minimize the effect of endogenous IGF-I or -II, this stimulation was decreased by about 50% in the presence of IDF45. This result suggests that addition of bFGF stimulates IGF secretion, thereby resulting in partial loss of inhibition, by IDF45, of bFGF stimulation.

Details

ISSN :
00219541
Volume :
149
Issue :
3
Database :
OpenAIRE
Journal :
Journal of cellular physiology
Accession number :
edsair.pmid..........d4808598dc106684661918a466f66cda