Kinetics of albumin- and alpha-fetoprotein-production during rat liver development
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Synthesis of most of the plasma proteins is one of the main functions of the hepatocytes. Albumin synthesis is quantitatively the most abundant. In the present study we investigated albumin- and alpha-fetoprotein-gene-expression, and the function of the secretory apparatus during rat liver development. To this purpose we used the method of radioactive biosynthetic labeling of newly synthesized albumin and alpha-fetoprotein (AFP) to monitor the secretory capacity of endodermal cells derived from ventral foregut region (embryonic day 10, E10), and of embryonic and fetal hepatoblasts. Synthesis and secretion of albumin and AFP were already detected in the low numbered ventral foregut endodermal cells; fibrinogen synthesis was detectable in the E12 hepatoblasts, which were in higher number. The whole secretory machinery was functional from the earliest stages of liver development, and the speed of secretion was comparable with that of the adult hepatocytes. There was almost 4-fold increase of hepatoblasts cell volume in fetal stage compared with embryonic stage. The model used suggests that the hepatocyte secretory apparatus is already functional before the emergence of the liver bud. This is the first comparative report to analyze the hepatocyte secretory function, cell proliferation and cell volume during liver development.
KeywordsSecretory apparatus Albumin Differentiation Cell volume Proprotein convertases Subtilisin-like proteinases
- Duncan SA, Manova K, Chen WS, Hoodless P, Weinstein DC, Bachvarova RF, Darnell JE (1994) Expression of transcription factor HNF-4 in the extraembryonic endoderm, gut, and nephrogenic tissue of the developing mouse embryo: HNF-4 is a marker for primary endoderm in the implanting blastocyst. Proc Natl Acad Sci USA 91:7598–7602PubMedCrossRefGoogle Scholar
- Sheikh N, Tron K, Dudas J, Ramadori G (2006) Cytokine-induced neutrophil chemoattractant-1 is released by the noninjured liver in a rat acute-phase model. Lab Invest 8:800–814Google Scholar