Intercellular bridges between oocytes in the chicken ovary

Summary Fine structural analysis of the functional (left) ovary of the newly-hatched chick reveals the presence of true intercellular bridges between developing oocytes in the early stages of the meiotic prophase. These structures are characterized by: 1) cytoplasmic continuity between the participating oocytes, 2) a dense, fibrillar material beneath the lateral limiting membrane and 3) numerous cellular organelles within their confines. In addition, microtubular elements, parallel to the long axis of the bridge, are routinely observed. This latter finding suggests that intercellular bridges originate through incomplete cytokinesis of mitotically active oogonia and that the dense material beneath the limiting membrane may represent the cortical microfilaments associated with the contractile ring. Functionally, these structures may serve as channels for transfer of nutrients and organelles between oocytes although the possibility that certain oocytes function as nurse cells, in the sense that these cells exist in invertebrate ovaries, seems unlikely. In addition, intercellular bridges may be responsible for both restriction of oogonial mitoses and meiotic synchrony.Partial support for this study was provided by grant DE-00241 from the National Institute for Dental Research administered by Dr. Melvin Hess. We gratefully acknowledge his support of the initial aspects of this study. We are pleased to express our appreciation to Mrs. Cindy G. Wilcox, Mr. Lloyd Thibodeau and Mr. Don Driscoll for their expert technical assistance.