Stimulation of polyphosphoinositide hydrolysis in Swiss 3T3 cells by recombinant fibroblast growth factors.

Mitogenic concentrations of recombinant acidic or basic fibroblast growth factor (FGF) stimulated the accumulation of [3H]inositol phosphates ([3H]IPs) in Swiss 3T3 cells pre-labelled for 48 h with [3H]inositol. Maximal effects were obtained at 0.3 ng/ml and 3 ng/ml for basic and acidic FGF, respectively. Higher doses of either factor led to a diminished stimulation. FGF also stimulated 45Ca2+ release from cells pre-labelled with the isotope. However, FGF-stimulated production of [3H]IPs and release of 45Ca2+ exhibited marked differences when compared with the responses to the peptide mitogen bombesin; the FGF responses were markedly slower and were not inhibited by phorbol esters.