Basic Fibroblast Growth Factor Affects DNA Synthesis And Cell Function And Activates Multiple Signalling Pathways In Rat Thyroid FRTL-5 And Pituitary GH3 Cells
We have used a recombinant human basic fibroblast growth factor (basic FGF) to study its effects on cell proliferation, gene expression and accumulation of cyclic AMP (cAMP) and inositol phosphates in two well-characterized endocrine cell lines, FRTL-5 rat thyroid and GH3 rat pituitary cells. Basic FGF induced a dose-dependent increase in mitogenesis (assessed by measuring incorporation of [3H]thymidine) in FRTL-5 cells (40 ng basic FGF/ml increased mitogenesis above the control value by 2148±108% (mean ±
We have shown that basic FGF has different effects on mitogenesis in the two cell lines; gene expression and accumulation of inositol phosphates were increased in both, whereas the intracellular concentration of cAMP was decreased. The actions of basic FGF may be mediated through both inhibition of adenylate cyclase and hydrolysis of phosphatidyl inositol bisphosphate as has been proposed for 3T3 fibroblasts. Our data suggest that there may be a physiological role for basic FGF in both thyroid and pituitary tissue.