Effects of acidic fibroblast growth factor and epidermal growth factor on subconfluent fetal rat calvaria cell cultures: DNA synthesis and alkaline phosphatase activity.

The effects of acidic fibroblast growth factor (aFGF) and epidermal growth factor (EGF) were examined in subconfluent fetal rat calvaria cell cultures, in the presence of 2% serum. Maximal effect of aFGF and EGF on DNA synthesis measured by [3H]thymidine incorporation was observed after 18 h. aFGF stimulated DNA synthesis by 3.5-fold with an ED50 of 0.75 ng/ml while a 2.3-fold EGF stimulation was recorded with an ED50 of 0.067 ng/ml. 5-Bromo-2-deoxyuridine staining showed a higher stimulation of proliferation in the scattered cells than in the cell clusters. An 18 h aFGF or EGF treatment decreased alkaline phosphatase (ALP) activity by 40 and 23%, respectively, as compared with control cultures. This inhibition was more pronounced after 48 h in the presence of the effectors but no modification of the ALP electrophoretic mobility was observed. These data suggest that aFGF is a less potent mitogen than EGF and a higher inhibitor of ALP activity in fetal rat calvaria cell culture.