Fig. 6. SHH is not sufficient to rescue capillary plexus formation in Fgf9^-/- lungs. E11.5 explant cultures of wild-type and Fgf9^-/- lungs were incubated with BSA (A,B) or SHH (C,D) for 24 hours. Fgf9^-/- lungs (B) formed a less dense capillary plexus compared with wild-type controls (A). In contrast to a wild-type lung (A,C), incubation of Fgf9^-/- lungs with SHH did not increase capillary plexus density (D). Scale bar: 50 µm.