Relationships of the Ovular Surface with Follicle Cells and Origin of the Zona Pellucida in Rabbit Oocytes

Abstract

Rabbit oocytes at different stages of growth were studied in the electron microscope. Particular attention was given to the relationship existing between follicle cells and the ovular surface. The observations made are consistent with the concept already sustained by many optical researchers that this relationship is contiguous and that no communications exist between the cytoplasm of the two types. In every case examined it was found that the prolongations of follicle cells contact the ovular surface or its microvilli. In young oocytes(those in which the follicle cells begin to separate from the oocyte) the follicle cells'' prolongations "are short and wide. A substance of amorphous appearance was seen inside and outside these prolongations. The substance strikingly resembles that which later constitutes the zona pellucida.