Localization and synthesis of alpha-fetoprotein in the chicken.

The localization and sites of synthesis of alpha-fetoprotein in chick embryos throughout development have been investigated using the combined techniques of immunofluorescence microscopy and tissue culture in the presence of radiolabelled amino acids, followed by immunoautoradiographic analysis. Alpha-fetoprotein is present in a range of embryonic tissues and especially concentrated in the yolk sac, liver and connective tissue. Analysis of culture fluids revealed that the yolk sac is the major site of alpha-fetoprotein synthesis with smaller, but significant quantities being produced by the liver. These results are discussed in relation to mammalian alpha-fetoprotein, and the merits of the chick embryo for studies on the biological function of AFP are considered.