Fig. 1. Temporal distribution of endogenous NOS isoforms during vascular development. (A) ERK2 normalized data for NOS protein expression in pooled in vivo grown E7.5, E8.5 and E9.5 yolk sacs. The broken line represents eNOS, whereas the unbroken black line represents iNOS (n=4, ^*P<0.05, ^**P<0.01). The quantified signals represent mean±s.e.m. The relative expression levels were compared with 7.5 dpc levels. (B) Representative western blot of the graphed data.