Figure 1.

Development of bile ducts. (A) Immunostaining analysis showed that bile duct development is initiated by the formation of asymmetrical primitive ductal structures (PDS). a′ is a magnified view of the region delineated in a. By the end of gestation, bile ducts had become radially symmetrical (i–k). (B) Serial sections shows the hilum-to-periphery development of bile ducts, with symmetrical ducts near the hilum and asymmetrical PDS towards the periphery. The position of the portal vein relative to the bile ducts is indicated (pv). pa, parenchymal side of PDS; po, portal side; *, lumens of developing bile ducts.