Growth of myoblasts in lipoprotein-supplemented, serum-free medium: regulation of proliferation by acidic and basic fibroblast growth factor.

BC3Hl myoblast cells seeded at low density on gelatin-coated dishes and exposed to a 1:1 (vol/vol) mixture of Dulbecco's modified Eagle's medium and Ham's F12 medium, proliferate actively when exposed to high density lipoproteins (HDL), transferrin, insulin, and basic or acidic fibroblast growth factor (FGF). This serum-free medium combination supported cell multiplication at a rate equal to that of serum-supplemented medium, and at low cell input (10(3) cells/35-mm dish). It also allowed serial transfer of the cultures under serum-free conditions. HDL seems to promote cell survival and to act as progression factor allowing cells to divide when exposed to either basic or acidic FGF. When the potency of basic and acidic FGF were compared, acidic FGF was 20-fold less potent than basic FGF.