CAPSULE Mechanisms that control the survival of oocytes and, by extension, the duration of ovarian function have been identified. However, it is still not clear whether oocyte "quality" is related to survival, nor is the role of the granulosa cells of follicles in follicle survival entirely understood. Here, we consider oocyte-intrinsic and oocyte-extrinsic mechanisms of oocyte loss and argue t...

Intracellular pH-regulatory mechanisms are acquired by growing mouse oocytes with meiotic competence, and these mechanisms become fully active when the oocytes develop to the germinal vesicle (GV) stage as shown in CF1 and Balb/c strains mice. On the other hand, there is some evidence showing that intracellular pH-regulatory mechanisms are inhibited at the stages of Metaphase I (MI) and II (MII...

Progesterone stimulates sperm functions, e.g. hyperactivation, acrosome reaction, binding to oocyte zona pellucida and penetration rate into the hamster oocyte. The physiological relevance of these effects has been shown using female genital tract fluids which modulate sperm function according to their progesterone content. Progesterone interacts with specific sperm binding sites that, unlike t...

The effect of estradiol E, progesterone P and testosterone propionate T upon growth and germ cell population of foetal ovaries transplanted under the kidney capsule of adult ovariectomized hamsters was examined. Foetal ovaries were obtained 15 days postcoitum and the host received daily subcutaneous injections of E (1 micrograms/day), P (5 mg/day), T (500 micrograms/day) or E + P in 0.1 ml oil ...

Polarity of the Drosophila oocyte is essential for correct development of the egg and future embryo. The Par proteins Par-6, aPKC and Bazooka are needed to maintain oocyte polarity and localize to specific domains early in oocyte development. To date, no upstream regulator or mechanism for localization of the Par proteins in the oocyte has been identified. We have analyzed the role of the small...

This study reports observations on fine-structural changes in the nucleus of the oocyte in hamsters during the establishment of the primordial (unilaminar) follicle at 7 to 12 days after birth. Following pachytene, the nuclei at early diplotene contain simple chromosomal cores surrounding by a sheath of fibrillo-granular material symmetrically disposed in the form of lateral projections and loo...

In spite of great efforts, the mechanisms for postovulatory oocyte aging are not fully understood. Although our previous work showed that the FasL/Fas signaling facilitated oocyte aging, the intra-oocyte signaling pathways are unknown. Furthermore, the mechanisms by which oxidative stress facilitates oocyte aging and the causal relationship between Ca2+ rises and caspase-3 activation and betwee...

Improved methods are needed to reliably and accurately evaluate oocyte quality prior to fertilization and transfer into the woman of human embryos created through in vitro fertilization (IVF). All oocytes that are retrieved and matured in culture are exposed to sperm with little in the way of evaluating the oocyte quality. Furthermore, embryos created through IVF are currently evaluated for dev...

Syrian hamster embryo fibroblasts transformed in vitro with benzo(a)pyrene were analyzed for the presence of type C viral components, including extra- and intracellular reverse transcriptase activity, intracellular type C hamster virus-related RNA, and cellular hamster virus group-specific antigen. No evidence could be obtained for the presence of any of these components, although they were eas...

Background: The cryopreservation of human oocyte would make significant contribution to fertility treatments. It could also provide on alternative to embryo preservation for avoidance ethical problems. Embryo cryopreservation is now a successful procedure, but oocyte cryopreservation has poorer results. Materials and Methods: For retrieval of oocyte NMRI mouse were used. after administration of...