Fig. 5. (A) Individual FGFs and BMPs have distinct morphological effects on isolated epithelium cultured in growth factor-reduced Matrigel for 44 hours. FGF1-, FGF4- and FGF10-treated epithelium form duct-like structures, whereas FGF2 and FGF7 promote bud formation. Epithelium treated with FGF8, BMP4 or BMP7 alone do not grow. Numbers indicate concentrations in ng/ml. (B) Combinations of FGFs resulted in phenotypes with more complex morphology than any growth factor alone. FGF4/FGF1 resulted in larger glands with longer ducts. FGF10/FGF2 and FGF7/FGF1 both resulted in elongated stalks and enlarged buds. Combinations of FGF10 or FGF7 with either BMP4 (shown) or BMP7 (similar result, not shown) did not grow, suggesting BMPs antagonize FGF7 and FGF10. FGF2/FGF7/FGF10 resulted in multiple stalks and buds. FGF1/FGF2/FGF10 resulted in the most complex morphology with elongated ducts, multiple branch points and enlarged terminal epithelial buds. Scale bars: 200 µm.