Dual effect of activin A on cell growth in Balb/c 3T3 cells.

Effects of activin A on cell growth were studied in Balb/c 3T3 cells. When incubated with serum, activin A inhibited serum-induced increase in DNA synthesis in a concentration-dependent manner. Activin A also inhibited serum-induced increase in cell number. When added in quiescent cells, activin A did not affect competence-inducing activity of PDGF. Activin A by itself had a small competence-inducing activity. In contrast, when added in competent cells, activin A inhibited progression activity of platelet-poor plasma. These results indicate that activin A has dual action on cell proliferation in Balb/c 3T3 cells.