Characterization of embryonic antigens in the plasma of developing chick embryos.
Two prominent alpha-fetoproteins are found in chick embryo plasma up to and slightly beyond hatching. Only antisera against chick embryo plasma resolve them. alpha3-fetoprotein is a lipoprotein, the first fetoprotein thus described. It probably functions to transport lipid from the yolk to the embryo. The other fetoprotein (alpha4) is a major glycoprotein. Both are made by the liver and yolk sac. From 9 days onward, albumin is the principal export protein of the liver; at 7 days, when it first appears in the plasma, the yolk sac, but not the liver, makes it. The reverse situation occurs at 9 days. These facts suggest a humoral relationship between the yolk sac and liver. The embryo synthesizes every plasma protein including fetoproteins and "adult" proteins (prealbumin, albumin, and transferrin). No "cold" or unlabeled proteins are seen.
D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D002642:Chick Embryo / Q000276:immunology / Q000378:metabolism*; D005260:Female; D006023:Glycoproteins / Q000378:metabolism; D007122:Immunoelectrophoresis; D066298:In Vitro Techniques; D008074:Lipoproteins / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D012709:Serum Albumin / Q000096:biosynthesis; D014817:Vitelline Membrane / Q000378:metabolism; D000509:alpha-Fetoproteins / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*
D001798:Blood Proteins; D006023:Glycoproteins; D008074:Lipoproteins; D012709:Serum Albumin; D000509:alpha-Fetoproteins