Evolution of germinal epithelium in the chick ovary during embryogenesis

In previous works we showed a probable relationship between plasma membrane and its differentiations in ovary epithelium with maturation of the left ovary in chick embryo. To elucidate this aspect a cytochemical and ultrastructural study of the germinal epithelium from 7 to 19 days-old chick embryos was performed. Cytochemical and ultracytochemical techniques for mucosubstances localization and transmission electron microscopy were used. At 7 days the epithelium of right and left ovary showed epithelial cells with microvilli and junctional complexes. Irregular folds and projections appeared in the germ cells. Both cell types possessed a coat with a light reaction in the right gonad and more intense in the left one when they were stained with Alcian blue, PAS or Ruthenium Red. From 11 to 19 days, in the left ovary epithelium the layers of cells were increased and presented discontinuous basement membranes and absence of cell projections. On the contrary, in basal and germ cells these structures were increased. The mucosubstances increased from the 15th day. At this time the right ovary showed a simple epithelium with cells without projections. The germ cells disappeared in this ovary and a marked decrement of mucosubstances was observed. These results indicate that it exists a direct relationship between cellular morphogenesis and the mucosubstances of membranes. These substances may play a special role in the cellular migration of the left ovary since they were not detected in the right gonad which suffers regression and embryonic atrophy.