After migration of hepatoblasts into the septum transversum mesenchyme, the hepatic architecture begins to be established, with liver sinusoids and bile canaliculi appearing. The liver bud separates into the lobes. The left umbilical vein becomes the ductus venosus and the right vitelline vein becomes the portal vein . The expanding liver bud is colonized by hematopoietic cells . The bipotential hepatoblasts begin differentiating into biliary epithelial cells and hepatocytes . The biliary epithelial cells differentiate from hepatoblasts around portal veins, first producing a monolayer, and then a bilayer of cuboidal cells. In ductal plate, focal dilations emerge at points in the bilayer, become surrounded by portal mesenchyme, and undergo tubulogenesis into intrahepatic bile ducts. Hepatoblasts not adjacent to portal veins instead differentiate into hepatocytes and arrange into cords lined by sinudoidal epithelial cells and bile canaliculi. Once hepatoblasts are specified into hepatocytes and undergo further expansion, they begin acquiring the functions of a mature hepatocyte, and eventually mature hepatocytes appear as highly polarized epithelial cells with abundant glycogen accumulation. In the adult liver, hepatocytes are not equivalent, with position along the portocentrovenular axis within a liver lobule dictating expression of metabolic genes involved in drug metabolism, carbohydrate metabolism, ammonia detoxification, and bile production and secretion. WNT/β-catenin has now been identified to be playing a key role in this phenomenon. 
NEXAVAR may interact with certain other medicines and cause serious side effects so tell your doctor about all medicines you take including prescription and over-the-counter (OTC) medicines, vitamins, or herbal supplements. Especially tell your doctor if you are taking the following medicines: warfarin (Coumadin, Jantoven ® ), neomycin, St. Johns Wort, dexamethasone, phenytoin (Fosphenytoin sodium, Dilantin, Phenytek), carbamazepine (Carbatrol, Equetro, Tegretol, Teril, Epitol), rifampin (Rifater, Rifamate, Rifadin, Rimactane), rifabutin (Mycobutin), phenobarbital.