Human fallopian tube epithelium cytochemistry in the first and third trimesters of pregnancy.

The human Fallopian tube fimbrial epithelium was histo- and cytochemically studied in the first and third trimesters of pregnancy. In the first trimester morphometric measurements confirmed a decrease in cell size and a reduction in ciliary cell count. The ciliary cell population was surprisingly glycogen-poor, and some of the cell contained, among normal organelles, lipid accumulation, lamellated bodies and nuclei with slightly condensed chromatin. Some had defective cilia and basal bodies. Large globules, containing few lipid droplets and glycogen rosettes were demonstrated. The bulk of the globules, however, contained an unidentified electron-lucid substance, negative to PAS, Alcian blue, OsO4 and the Millon reactions, but positive to acid phosphatase reaction, the products of which appeared dispersed. The nonciliary cell population was heterogeneous; some appeared almost devoid of microvilli and had dilated RER and SER cisternae, lamellated bodies and condensed nuclear chromatin. In some cells a single centrally located cilium was noticed. Other nonciliary cells had extensive microvilli and appeared less atrophied. In the third trimester morphometric, as well as cytochemical methods indicated that the regressive process was beginning to reverse itself. Alkaline-phosphatase reaction products appeared along the apical and lateral membranes of the nonciliary cell. Acid-phosphatase reaction products depicted the lysosomes, present in both types of cells.