Basic fibroblast growth factor stimulates the competence phase of subcultured endothelial cells and the progression phase of primary cultured smooth muscle cells from rat aorta.

The proliferative effects of basic fibroblast growth factor (bFGF) on the cell cycle were compared in subcultured endothelial cells (EC) and primary cultured smooth muscle cells (SMC) from rat aorta by monitoring the starting time (an index of the competence phase) and rate (an index of the progression phase) of [3H]thymidine incorporation. Persistent treatment with bFGF (1, 10 and 30 ng/ml) reduced the starting time of EC proliferation in the presence of 1% fetal bovine serum (FBS) in a concentration-dependent manner. The starting time of [3H]thymidine incorporation into EC was reduced by a maximum of 4 h by pretreatment with bFGF for 12 h but not for 3 h. DNA synthesis in EC was inhibited by pretreatment with bFGF for 24 h. The rate of [3H]thymidine incorporation into SMC was accelerated both by persistent treatment with bFGF and pretreatment for 3 h in the presence of 3% FBS. In serum-free medium, bFGF (30 ng/ml) stimulated [3H]thymidine incorporation into SMC but not into EC after incubation for 36 h. Together, bFGF (10 ng/ml) and insulin (10 micrograms/ml) synergistically stimulated [3H]thymidine incorporation into EC, but insulin alone did not. These findings indicate that bFGF is a competence factor in EC and a progression factor in SMC from rat aorta.