Decidual tissue in the human ovary obtained from 53 women by gynecological operation or cesarean section at 8-42 weeks of normal pregnancy was studied by light and electron microscopy.
Histologically, ovarian decidual cells had round nuclei with prominent nucleoli and abundant eosinophilic cytoplasm. Immunoreactive prolactin was detected in the cytoplasm of some decidual cells.
Electron microscopically, nuclei were oval or ellipsoidal in shape with distinct nucleoli and enchromatin. The cytoplasm contained well developed rough and smooth endoplasmic reticulum, Golgi apparatus, abundant rod-shaped mitochondria, intermediate filaments, glycogen particles and lysosomes. Peduncular protrusions containing secretory bodies bounded by a limiting membrane were characteristically observed. Some protrusions showed exocytosis of secretory bodies composed of numerous granular contents. Acid phosphatase (AcPase) activity was demonstrated in the secretory bodies by a cerium-based method in combination with a microslicer. Periodic acid-silver methenamine (PA-silver . methenamine) technique also revealed deposits of silver in the secretory bodies.
These findings strongly suggest that ovarian decidual cells secrete granular contents positive for AcPase and PA-silver methenamine reactions from the peduncular protrusions with the mode of exocytosis and some decidual cells contain prolactin in the cytoplasm. These are quite similar to uterine decidual cells.