objective: mitochondria is a critical organelle within the cell and has important role in the oocyte development, thus the aim of this study was the comparison of mitochondrial distribution within the mouse oocyte at germinal vesicle (gv), germinal vesicle breakdown (gvbd) and metaphase ii (mii) stages using laser confocal microscopy (lscm). materials and methods: after superovulation of adult...

objectives: it was aimed to investigate the effects of different doses of follicle stimulating hormone (fsh) and activin a on the growth and maturation of preantral mouse follicles during the in vitro culture. methods: preantral follicles (90-100 µm in diameter) were harvested from 6-8 week-old syrian mice and cultured in tcm199 culture medium for 6 days to see the effect of fsh and activin a. ...

developing a culture system for preantral follicles has important biotechnological implications due to the potential to produce a large number of oocytes for embryo production and transfer. to accomplish this goal, the present study was aimed to culture preantral follicles in the presence of different media, sera and fsh concentrations. six-week-old preantral follicles (95 ± 5 µm) were cultured...

Various stages of immature human oocytes were imaged for microtubule, microfilament and chromatin organization. After germinal vesicle breakdown, a small microtubule aster was observed near the condensed chromatin. The asters appeared to elongate and encompass the condensed chromatin. At metaphase I stage, microtubules were detected in the meiotic spindle. The meiotic spindle in metaphase II wa...

Cytoplasmic extracts of meiotically mature mouse oocytes were injected into immature Xenopus laevis oocytes, which underwent germinal vesicle breakdown within 2 h. Germinal vesicle breakdown was not inhibited by incubation of the Xenopus oocytes in cycloheximide (20 micrograms/ml). Identically prepared extracts of meiotically immature mouse oocytes, arrested at the germinal vesicle stage by dib...

Meiotic reinitiation of the mouse oocyte is characterized by a slow entry into metaphase I, beginning with germinal vesicle breakdown and ending with spindle formation. It is accompanied by a cascade of protein kinases and phosphatases increasing protein phosphorylation. The activation of histone H1 kinase and that of the mitogen-activated protein kinase p42 have been compared during spontaneou...

It is demonstrated that the microinjection of cytoplasm from competent, fully grown oocytes can induce germinal vesicle breakdown in meiotically incompetent growing oocytes. Injection of cytoplasm from oocytes at methaphase I had a similar effect. The maturation in injected growing oocytes was arrested at the premetaphase or metaphase I stage. Induction of germinal vesicle breakdown by cytoplas...

In this study, we investigated the spatio-temporal distribution of conventional protein kinases C (cPKC) isoforms PKC-alpha, PKC-betaI, PKC-betaII and PKC-gamma in mouse oocytes. The cPKCs were present in the cytoplasm at the start of the process and migrated to the nucleus (or germinal vesicle) before germinal vesicle breakdown, except for PKC-gamma which remained cytoplasmic. In both compartm...

We recently identified Xenopus Rho-associated protein kinase alpha (xROKalpha) as a Xenopus insulin receptor substrate-1 binding protein and demonstrated that the non-catalytic carboxyl terminus of xROKalpha binds Xenopus insulin receptor substrate-1 and blocks insulin-induced MAP kinase activation and germinal vesicle breakdown in Xenopus oocytes. In the current study we further examined the r...