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An IGF binding protein is an inhibitor of fgf stimulation
Author(s) -
Villaudy J.,
Delbé J.,
Blat C.,
Desauty G.,
Golde A.,
Harel L.
Publication year - 1991
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041490319
Subject(s) - stimulation , basic fibroblast growth factor , fibroblast growth factor , growth factor , endocrinology , embryo , medicine , biology , dna synthesis , endogeny , somatomedin , homologous chromosome , dna , microbiology and biotechnology , biochemistry , receptor , gene
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. IDF45 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.