Branching morphogenesis in a rat lung explant system. (A) Representative examples of control and fetal lung explants treated with ANGII at 10−9 mol/L, ZD-7155 (an AT1-antagonist) or PD-123319 (an AT2-antagonist). Original magnification 25×. (B) Number of total airway buds of lung explants treated with increasing ANGII concentrations or (C) with ZD-7155 (ZD), PD-123319 (PD), ANG 10−9 + ZD or ANG 10−9 + PD. Results are expressed as ratio of d 4 (D4) and d 0 (D0) of culture (D4/D0 ratio). P < 0.05: *versus ANGII at 0 mol/L (control, C), §versus ANGII at 10−9 mol/L, †versus ZD-7155 at 10−5 mol/L, ‡versus ANG 10−9 + ZD.