Studies on the Human Oocyte and Its Follicle

Abstract

Oocytes in primordial ("resting") follicles in adult human ovaries contain a complex paranuclear structure identified by light microscopists as Balbiani's vitelline body. By electron microscopy this structure is composed of a mass of mitochondria with associated endoplasmic reticulum, multiple compound aggregates which form a ring around the cytocentrum, and a single stack or coil of annulate lamellae either attached to the nuclear membrane or free in the cytoplasm. The compound aggregates contain vacuoles and finely divided electronopaque material Evidence is presented for the probable transport of this material between the oocyte and its environment. The cytocentrum contains a central aggregate of amorphous electron-opaque deposits which appear to become periodically aligned on fine fibrils to form the long coarse fibers at the periphery of the cytocentrum. The apparent prevalence of annulate lamellae attached or adjacent to the nuclear membrane of oocytes in ovaries removed during the mid-follicular (estrogenic) phase of the cycle indicates the need for further study of a possible hormonal influence on the resting oocyte. By light microscopy phosphatases were not found within the oocyte, but adenosine-monophosphatase activity is present in the cortical cells surrounding primordial follicles, and also at the periphery of each primitive follicle cell, most prominently at the oocyte side. Glucose-6-phosphate dehydrogenase activity is present within the oocyte cytoplasm.

Light microscopical and ultrastructural characterization of goat preantral follicles

“…In general, the ultrastructure of goat preantral follicles was similar to that of other mammalian species (cattle - Van Wezel and Rodgers, 1996, Fair et al, 1997bpig -Greenwald and Moor, 1989;feline -Jewgenow and Stolte, 1996;humanHertig andAdams, 1967 andOktay et al, 1997), but some differences were observed, which may indicate either species specific differences or different phases of follicular development.…”

Cumulus cell contact during oocyte maturation in mice regulates meiotic spindle positioning and enhances developmental competence

“…Those that survive this process are ovulated and undergo the final phases of maturation that prepare the nucleus and cytoplasm for embryogenesis. Throughout oogenesis in mammals, oocytes maintain physical contact with follicular somatic cells via granulosa cell extensions known as transzonal projections (TZPs) [1,6,23,33,43,44]. Despite the recognized functions of TZPs in gap junction mediated metabolite exchange, heterocellular adhesion, cell cycle regulation and bidirectional signaling [10,18,40,47], the precise role these structures play in the acquisition of developmental competence during oocyte maturation is unknown.…”

The human VASA gene is specifically expressed in the germ cell lineage

“…6A). The location of this body corresponds to the so-called ''yolk nucleus'' of Balbiani's vitelline body, described ultrastructurally in detail by Hertig and Adams (22) in human primordial follicles. Immunostaining of this body was not observed with preimmune sera or antisera to other ovarian antigens such as inhibin and depended on the presence of primary antibody (data not shown).…”