Cellular Distribution of Serum α-Foetoprotein in Organs of the Foetal Rat

Abstract

THE mammalian foetus synthesizes a serum α-globulin, called α-foetoprotein, which is not found in the adult of the species^1–7. Although interspecies structural differences among the α-foetoproteins have been noted^4–7, the protein of each species appears to be a homologue of foetuin, or bovine α-foetoprotein^5,7. Synthesis of serum α-foetoprotein has been shown to occur in the liver in both the rat foetus^8,9 and the human embryo⁹, and in the yolk sac of the rat⁹. The cells responsible for this synthesis are not known, however, and it has been suggested that the haematopoietic tissue of the liver may be the site of synthesis⁸. In the present investigation, the cellular distribution of α-foetoprotein in organs of the rat foetus was investigated by means of the fluorescent antibody method.