Endometrium of early pregnancy were compared with nonpregnant endometnum by inimunohistochemical and ultrastructural techniques with respect to glandular and stromal elements of endometrium. The results obtained were as follows: 1. The AS cell in decidua has all the features of actively secreting glandular epithelium and shows the pronounced arrays of glandular endoplasmic reticulum and moderate numbers of ribosomes ultrastructually. Therefore the AS cell indicate considerable protein production, presumably contributing to both cell gowth and the production of secretions. 2. The process of decidualization can be characterized morphologically and immunohistochemically by the accumulation of basement membrane-like materials, such as laminin and type IV collagen which may be related to the hormonal stimulation occuring during pregnancy and trophoblastic attachment. 3. The decidual cells show strong positive for vimentin and some large mature decidual cells show weakly positive for lysozyme and cti- antitrypsin, which might represent more the sequential differentiation of stromal cells into decidual cells than origin of histiocytes. 4. Immunoreactivity with S-100 protein was found in glandular and stromal cells of decidua but negative in endometrium of nonpregnant women. So some humoral factors related to pregnancy stimulate expression of S-100 protein in glandular and stromal cells of decidua.
Pregnancy ; Female ; Humans