The effect of interleukin-1alpha (IL-1alpha) on the production of basic fibroblast growth factor (bFGF) in human gingival fibroblasts originated from a nifedipine-reactive patient was investigated. Ca(2+)-mobilizing agents, thapsigargin and bradykinin, were also tested to determine whether they affected the production and release of bFGF. The release of bFGF from IL-1alpha-pretreated cells in relation to the transient increase in intracellular Ca(2+)([Ca(2+)]i) and extracellular Ca(2+)levels was also investigated. IL-1alpha and thapsigargin yielded significantly higher bFGF production, and also enhanced bFGF mRNA expression. IL-1alpha-pretreated cells showed significantly greater release of bFGF under the present experimental conditions. Levels of released bFGF were significantly higher in cells pretreated with IL-1alpha, followed by bradykinin and thapsigargin in the presence of extracellular Ca(2+). The transient mobilization of intracellular Ca(2+) accelerated the release of bFGF in IL-1alpha-pretreated cells, but not in untreated cells. Thus, IL-1alpha increases bFGF production in nifedipine-reactive gingival fibroblasts and also influences the release of bFGF in the IL-1alpha-pretreated cells.