[Immunohistochemical studies of the localization of prolactin in human term chorion laeve].

Human amniotic fluid contains a very high concentration of PRL. And it is widely accepted that decidual cells are the origin of amniotic fluid PRL, and decidual cell PRL is transported into amniotic fluid across the fetal membranes. However, the decidual cells are, in their lower aspect, in contact with chorion cells. Because of this complex structural relationship, decidual cells are often called decidua-chorion cells, besides, chorion PRL reproduction remains to be elucidated. Consequently, we further examined tissue of chorion laeve which had been obtained at spontaneous term vaginal delivery. The results of our examinations are as follows; 1. Chorion PRL was determined with precipitation method of radioimmunoassay, and it was concluded that chorion tissue contains no small amounts of human PRL; 391 +/- 24 ng/g in tissue, whereas decidual PRL was 225 +/- 91 ng/g in tissue. 2. Using immunohistochemical procedures and PAP complex methods, immunized anti-ovine PRL serum revealed PRL reactivity around the numerous granules or globules in term chorion cells. These data suggest that the chorion cells are the site of reproducible PRL localization and synthesis and, comparable to decidual cells, are the possible source of human PRL in term fetal membrane.