Tissue expression of VEGF is elevated in ALK1^+/−mice. RNA and protein were prepared from aorta, lungs, liver, and intestine from wild-type (wt) and ALK1^+/− mice. Expression of VEGF and ALK1 was determined by real-time PCR and immunoblotting. Asterisks indicate statistically significant differences compared with control (wt). **P < .01; ***P < .001; Tukey test.