No abstract

Rat monoclonal antibodies to human progesterone receptor were used for immunolocalization studies in human decidua of early pregnancy. Frozen sections of 42 specimens of decidua were stained by the peroxidase-antiperoxidase method (PAP). Progesterone receptor was localized exclusively in the nuclei of decidual and myometrial cells with no specific staining in the cytoplasm. In the decidualized endometrium, stroma were always positively stained. Smooth muscle, pericyte and endothelial cells of blood vessels were extensively stained. Glandular epithelia showed variation in staining, which was positive in the basal but very weak or negative in the superficial layer of the decidua. No specific staining could be detected in the control sections. Of special interest was the positive staining of the endothelium of decidual blood vessels, a finding which has not been reported previously. The cells of the inner lining of vessels that stained with the antiprogesterone receptor antibodies were also Factor VIII positive, thus confirming the endothelial nature of these cells. It is concluded from these results that endothelial cells from human first trimester decidua express progesterone receptors.

No abstract

The aim of our study was to localize oestrogen receptor (ER) and progesterone receptor (PR) in the trophoblast population at the maternofetal interface in early pregnancy. Rat monoclonal antibodies to human ER and PR were used to study 44 cases of chorionic villi and 82 cases of decidua using an immunocytochemical method. The PR-immunoreactive products were localized in the nuclei of syncytiotrophoblast and cytotrophoblast cells of the villi. Specific staining was also present in the cytoplasm. Villous stroma and vessels were stained occasionally. Using cytokeratin staining in an adjacent section or double staining with PR and cytokeratin, the distribution of invading trophoblast cells and their PR expression were examined. In decidual stroma, a type of interstitial cell was identified which simultaneously expressed cytokeratin and PR in the cytoplasm, indicating that the invading trophoblast cells may express PR. All extravillous populations at the interface were positive for PR, including the syncytial lining of the decidual surface, the cytotrophoblast column, the cytotrophoblast shell and the interstitial trophoblast. The immunoreactivity of PR was also localized in the nuclei of vascular endothelial cells, whereas Factor VIII was localized in the cytoplasm of the same cells, thus confirming their endothelial nature. In contrast to PR, little ER could be detected in the trophoblast cell population using anti-ER antibody D75 in our study.

A total of 60 women with 6-7 weeks' amenorrhoea were randomly allocated to three groups. The women in the first group (control) took a placebo 24 h before undergoing vacuum aspiration. The subjects in the second and third groups were given orally 200 mg of RU 486, 12 or 24 h before surgical interruption of their pregnancy. Villi and decidua were collected and frozen in liquid nitrogen. There were no significant differences in villous cytosolic steroid concentrations between the control and RU 486-treated groups. The RU 486 concentration was lower in villous cytosol than in decidua and serum. The immunostaining of progesterone receptor in villous and extravillous trophoblast was weak and localized in both cytoplasm and nucleus. RU 486 treatment had no effect on the immunostaining of progesterone receptors in trophoblast populations except in the placental bed giant cells, where the weak and diffuse progesterone receptor staining in the cytoplasm of controls seemed to be concentrated in the nucleus after RU 486 treatment. In conclusion, RU 486 might have no effect on the immunostaining of progesterone receptor and on steroid concentrations in villi in vivo.