Mouse brain extract with "fibroblast growth factor"-activity.

Crude tissue extracts prepared by homogenization and ammonium sulfate precipitation of mouse brains as described by Gospodarowicz et al. (1975) for brains and hypophyses of cattle have also been found to contain fibroblast growth factor-activity. In the presence as well as in the absence of calf serum in the medium the survival and proliferation of primary mouse embryo fibroblasts in culture were promoted as documented by dose-dependent increase of cell number and protein content during an incubation period of 48 hours. In the case of serum-free incubation also a significant rise of thymidine incorporation induced within 24 hours by the extract was noted. In contrast, the proliferation of primary chicken embryo fibroblasts or transformed mouse cells of the line "L" was not stimulated. Some possibilities for a practical use of such extracts are discussed.