F9 cells can be stimulated to differentiate into parietal endoderm in the presence of retinoic acid and dibutyryl cyclic AMP （cAMP）; Differentiating cells synthesize plasminogen activator, laminin and type IV collagen; CAMP is active only on cells that have been treated with retinoic acid; Tested and found negative for ectromelia virus （mousepox）; Culture vessels must be coated with 0.1％ Gelatin prior to use. To do so, cover the surface to of the vessel with 0.1％ Gelatin （Difco） in sterile distilled water for 2 hours at 4C, then wash three times with sterile distilled water. Treated flasks and dishes can be stored at room temperatureTumorigenecity： Isoenzyme： Histopathology： teratoma, testicular; Embryonal carcinomaSubculture： Split ratio： Media change： Reverse transcritase： Productionplasminogen activator; Laminin; Type IV collagen.
