Institut de Recherches Scientifiques sur le Cancer , Villejuif , France .
Biol Cell 76 : 125-30 ( 1992)
Abstract
Our results show that stimulation by serum of dense cultures of 3T3 cells rapidly induced increased synthesis of a growth inhibitor ( mIGFBP-3 ) capable of binding IGF .
mIGFBP-3 was secreted by stimulated cells immediately after its synthesis , and accumulated in the medium .
Accumulation of mIGFBP-3 in the medium increased , as a function of growth factor ( bFGF , PDGF , insulin ) concentrations and time .
bFGF was the best stimulatory factor for both DNA synthesis and accumulation of mIGFBP-3 in the first 24 h of incubation .
DNA synthesis was arrested after 48 h of incubation with bFGF when accumulation of mIGFBP-3 was maximal .
Since we showed that mIGFBP-3 is able to inhibit bFGF stimulation of DNA synthesis in mouse fibroblasts , it is possible that the accumulation of mIGFBP-3 induces a feedback regulation of cell growth .