Development of the zona pellucida in the rat oocyte

Abstract

Abstract Ovaries of weanling and juvenile rats were studied by electron microscopic and cytochemical techniques, with particular reference to the role of the Golgi complex in the formation of the zona pellucida. The zona pellucida type of material first appears in the perivitelline space at the stage when the oocyte acquires a single layer of flattened and cuboidal granulosa cells, and is completely formed when the granulosa cells attain a cuboidal shape. The intimate association of the Golgi complex with the oocyte plasmalemma and the presence of mucopolysaccharide in its saccules and vesicles suggests that the Golgi complex of the oocyte plays an important role in the synthesis of the zona pellucida. The zona pellucida of the rat egg consists of a single layer of acid mucopolysaccharide which is structurally distinguishable from the liquor folliculi. Formation of the primary liquor folliculi is attributed to the Golgi complexes in granulosa cells.