Cytochrome P450 1b1 (Cyp1b1) is expressed in a spatial and temporal manner during development, notably in rhombomere 4 of the neural crest, the hind brain and the eye [1–3]. Human developmental aberrations in both the eye [3] and the liver [4] arise from Cyp1b1 deficiency. Cyp1b1 is expressed in multi-potential mesenchymal stromal cells [5], liver stellate cells [6–7], endothelium [8–9] and microvessels of the brain [10]. Cyp1b1 is, however, essentially absent from adult mouse hepatocytes [7, 11]. Effects of Cyp1b1 deletion on the vasculature depend on increased oxidative signaling [8–9] and diminished estrogen metabolism [12].
