RESUMO
Two hepatotrophic protein factors (HTF) were partially purified from the serum-free conditioned medium of the embryo rat fibroblastic cell line FRL. HTF induced cell adherence to the culture plate, promoted life maintenance, scattering and enhanced 3H-Thymidine uptake into DNA and cell proliferation in two sensitive murine non-transformed, epithelial hepatocytic cell lines (C6 and C2.8). In this bio-assay, cells were plated at low density in Dulbecco's Modified Eagle's Medium, in the absence of serum and other exogenous growth factors. HTF did not synergize with epidermal growth factor. Biological activity was associated to two major acidic proteins: a non-heparin-binding protein (M(r) approximately 70 kDa, pI 4.6-4.5) and a heparin-binding protein (M(r) approximately 200 KDa, pI 4.3-4.1).
