The ultrastructure of follicle cells in fetal guinea-pig ovaries.
The development of the follicle cells in fetal guinea-pig ovaries has been examined in the electron microscope. The findings were as follows: at days 34 and 38 there were broad intercellular clefts within the germinal cords. However, a continuous layer of thin cytoplasmic processes from the follicle cells separated the germinal cords from the stromal compartment. The germinal cords were everywhere limited by a basal lamina. During all the period examined coated vesicles, possibly emptying their contents into the region of the basal lamina, were observed in the follicle cells. At days 42, 46 and 50 the cellular membranes were closely apposed with an intercellular distance of about 200 A. Complexes of deeply interdigitating folds of the membrane of neighboring follicle cells were observed. The follicle cells forming part of the primordial follicles at days 54 and 58 were characterized by a disappearance of these folds and by the appearance of bundles of microfilaments in the cytoplasm. These were especially numerous at day 66. At days 34 and 38 gap junctions were observed between the follicle cells, but not between the follicle cells and the germinal cells. During the entire period examined junctions resembling desmosomes without filaments were observed between the follicle cells as well as between the follicle cells and the germinal cells. The ultrastructure of the follicle cells is considered in detail and the functional significance of the findings discussed.
D000818:Animals; D002462:Cell Membrane / Q000648:ultrastructure; D002467:Cell Nucleus / Q000648:ultrastructure; D003896:Desmosomes / Q000648:ultrastructure; D005260:Female; D005333:Fetus; D006168:Guinea Pigs; D006080:Ovarian Follicle / Q000648:ultrastructure*; D010053:Ovary / Q000196:embryology*; D011247:Pregnancy