GAP JUNCTIONS BETWEEN OOCYTE AND COMPANION FOLLICLE CELLS IN MAMMALIAN OVARY

Tracer and freeze-fracture electron microscopy of the ovaries of neonatal rat and adult mouse, rat, rabbit and primate [Macaca mulatta] revealed the presence of gap junctions between follicle cells and oocytes. The junctional connections are found at the ends of follicle cell projections which traverse the zona pellucida and terminate upon microvilli and evenly contoured nonmicrovillar regions of the oolemma. Gap junctions are often seen associated with a macula adherens type of junction. The gap junctions occasionally consist of minute ovoid plaques but more frequently appear as rectilinear single- or multiple-row aggregates of particles on the P-face or pits on the E-face. The functional significance of follicle cell-oocyte gap junctions is discussed with respect to the regulation of meiosis and luteinization.