Some culture systems have been shown to support oocyte growth in mice, although there has been little success in applying these systems to other species. In the present study, we compared three culture conditions for growing bovine oocytes and examined the effect of hypoxanthine on oocyte growth. In the first experiment, early antral follicles, 0.4-0.7 mm in diameter were collected, and oocyte-...

Mitochondria (mt) have been reported to be closely related to the maturation of mammalian oocytes, but their function in oocyte maturation has not been elucidated. In this study, we examined the kinetics of mt and chromatin configuration during in vitro maturation of mouse oocytes to clarify the relationship between oocyte maturation and mitochondrial distribution morphologically. Oocytes were ...

The oocyte meiotic spindle is comprised of microtubules (MT) that bind chromatin and regulate both metaphase plate formation and karyokinesis during meiotic maturation; however, little information is known about their role in meiosis reinitiation. This study was conducted to determine if microtubule integrity is required for meiotic induction and to ascertain how it affects activation of AMP-ac...

To study the mechanisms involved in the progression of meiotic maturation in the mouse, we used oocytes from two strains of mice, CBA/Kw and KE, which differ greatly in the rate at which they undergo meiotic maturation. CBA/Kw oocytes extrude the first polar body about 7 hours after breakdown of the germinal vesicle (GVBD), whilst the oocytes from KE mice take approximately 3-4 hours longer. In...

Exposure of mammalian oocytes to the protein phosphatase (PP)-1 (PP1) and PP2A inhibitor okadaic acid (OA) stimulates oocyte meiosis. However, treated oocytes do not develop beyond metaphase I (MI), and they display morphological aberrations. Experiments were conducted to define inhibitor treatment conditions for macaque oocytes that would result in germinal vesicle breakdown (GVB) stimulation ...

The objective of this study was to investigate the possible effect of demecolcine, a microtubule-disrupting reagent, on induced enucleation (IE) of sheep meiotically maturing oocytes. Immunofluorescent staining with anti-tubulin antibodies was used to examine the spindle status of the oocytes. When the oocytes with intact germinal vesicles (GV) were cultured in the medium containing various con...

In amphibians, as well as in other vertebrates, occytes start to mature under the action of hypophyseal gonadotropic hormones. (In this paper the term 'maturation' implies the transformation into ripe eggs of oocytes that have finished growing.) In the course of maturation the oocytes themselves and the follicle cells surrounding them undergo changes; the changes of these two cell types are not...

BACKGROUND In assisted reproductive techniques, 85% retrieved oocytes are mature, and the rest are immature. These immature oocytes may be matured in vitro, and used in subsequent in vitro fertilization program. The purpose of this study was to determine the maturation capacity and morphology of human immature oocytes in both fresh and vitrified-thawed, in vitro matured oocytes with regard to t...

Background In vitro maturation (IVM) of human oocytes has acquired increasing attention in infertility treatment with great promise. This technique is an alternative conventional in vitro fertilization-embryo transfer (IVF-ET), and can be reduced the side effects of gonadotropin stimulation such as ovarian hyperstimulation (OHSS). Oocyte maturation is a complex process including cytoplasmic and...