Localization of chorionic gonadotropin in the albino rat placenta was studied by an immunofluorescent staining method. Intense apple-green fluorescence was observed in the cytoplasm of the trophoblast giant cells of the junctional zone from the 12th to 19th day of pregnancy. The trophospongial cells and glycogen cells of the junctional zone, and decidual cells showed no distinct green fluorescence, but granular green fluorescence wasobserved in the cytoplasm of the trophoblast cell of the labyrinth from the 16th to 18th day of pregnancy. The epithelium of the amnion investing the fetal surface of the placenta and the umbilical cord, which is covered with a single layer of amnion cells, showed no fluorescence. Methyl-green pyronin positive substance (RNA) appeared in relatively large amounts in the cells of yolk sac, labyrinth, junctional zone, and decidua from the 8th day of pregnancy. Albino rat chorionic gonadotropin was localized mostly in the cytoplasm of the trophoblast giant cells in the junctional zone and a smaller amount in the trophoblast cells of the lobyrinth by means of the immunofluorescent technic.
Animals ; Chorionic Gonadotropin/*analysis ; Female ; *Fluorescent Antibody Technique ; Placenta/*analysis ; Rabbits ; Rats