Figure 2

Distribution of Crhr1 mRNA, Pomc mRNA, and immunoreactive (i) ACTH protein in mouse fetal lungs. Tissue sections are from GD 15.5 (A, B, F, G, K and L), 16.5 (C, H and M) or 17.5 (D, I and N). Adult mouse pituitary sections are used as positive control (E, J and O). In situ hybridization was performed using anti-sense probes (A to J, positive signal is blue), while immunohistochemistry was performed using an anti-iACTH polyclonal antibody (K to O, positive signal is red). No staining was observed using corresponding sense probes (negative controls, data not shown). On GD 15.5, expression of Crhr1 (A and B) and Pomc (F and G) was observed in cells surrounding airways and a change in expression sites toward distal epithelial cells was observed according to developmental time. On GD 15.5 (K and L), 16.5 (M), and 17.5 (N), iACTH was detected in epithelial cells. Scale bars, 100 μm (A, E, F, J, K and O) or 50 μm (B to D, G to I and L to N). AL, anterior lobe; CZ, conducting zone; E, epithelial cells; EC, endothelial cells; IL, intermediary lobe; M, mesenchyme; PL, posterior lobe; RZ, respiratory zone; SM, smooth muscle.