Assay for the Isolation of Hepatogenic Factors: Key Molecules in Hepatocyte Formation and Liver Morphogenesis

During embryonic development, pluripotent cells from the endoderm layer are directed toward specific cell lineages, leading to the formation of highly specialized organs, such as liver, lung, and pancreas. In case of liver, hepatocyte specification and maturation is the result of a tissue interaction between prehepatic endoderm and adjacent pre-cardiac mesoderm and, subsequently, the mesenchyme of the septum transversum. During these interactions, molecules regulating hepatogenesis (“hepatogenic factors“) are presented to the endoderm by the mesoderm (1 ,2 ). In rat, the inductive potential of the mesoderm (hepatogenic activity) is highest until embryonic day (ED) 12 and subsequently fades to background level, reached at ED 15 (3 ).