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Granulosa cells of mammalian Graafian follicles maintain oocytes in meiotic arrest, which prevents their precocious maturation. We show that mouse mural granulosa cells, which line the follicle wall, express natriuretic peptide precursor type C (Nppc) messenger RNA (mRNA), whereas cumulus cells surrounding oocytes express mRNA of the NPPC receptor NPR2, a(More)
Gonadotrophins and various growth factors, but not sex steroids, can induce resumption of meiosis in vitro, but only in oocytes enclosed by cumulus-granulosa cells. Follicular purines prevent resumption of meiosis. This process can be overcome, in vitro, by a transient elevation of cyclic AMP resulting in the production of a diffusible meiosis-inducing(More)
The present experiment used cultured mouse cumulus cell-enclosed oocytes (CEOs) and denuded oocytes (DOs) to study the function of nitric oxide (NO) in mouse oocyte meiotic maturation. Either positive or negative actions of NO on meiotic maturation has been observed when CEOs or DOs were cultured for 24 h in a medium containing 4 mM hypoxanthine (HX) to(More)
Although the effects of Gonadotropin on ovarian physiology have been known for many decades, its action on glucose uptake in the rat ovary remained poorly understood. Evidence also suggests that glucose uptake is mediated by a number of glucose transporter proteins (Glut). Therefore, we examined the rat ovary for the presence of Glut1-4 and blood glucose(More)
The mechanical method to isolate preantral follicle has been reported for many years. However, the culture systems in vitro are still unstable. The aim of this study was to analyze the effect of the culture system of mice preantral follicles on the follicular development in vitro. The results showed that the 96-well plate system was the most effective(More)
The present study is to investigate the immunolocalization of endothelial and inducible nitric oxide synthase (eNOS, iNOS) in porcine ovary and the effect of nitric oxide (NO) on antrum formation and oocyte meiotic resumption. In Experiment 1, preantral follicles (250-300 microm in diameter) were cultured in 0 (Control), 0.1, 0.3, 0.5 or 1 mM sodium(More)
Mammalian oocytes grow and undergo meiosis within ovarian follicles. Fully grown oocytes are arrested at the first meiotic prophase by a mural granulosa origin “arrester” until a surge of luteinizing hormone (LH) from the pituitary at the mid-cycle stimulates the immature oocyte to resume meiosis. Recent evidence indicates that natriuretic peptide precursor(More)
Meiosis-activating sterol (MAS) has been shown to induce mouse oocytes cultured in the presence of hypoxanthine (HX) to resume meiosis. The present research was conducted to determine whether amphotericin B or ketoconazole (a promoter and an inhibitor of production of MAS), affected oocyte maturation. Mouse cumulus cell-enclosed oocytes (CEO) or denuded(More)
In the process of oocyte maturation, gonadotrophins are believed as main stimulators for oocyte meiosis resumption. However, which gonadotrophin (i.e. FSH or LH) is the key hormone in this process is still unknown. This study indicated a close relationship between LH and FSH on activating meiotic maturation of oocyte in vitro. FSH efficiently induced oocyte(More)
Nitric oxide (NO) has been recently shown to act with a dual action in mouse oocyte meiotic maturation depending on its concentration, but the mechanism(s) through which it influences oocyte maturation has not been fully clarified to date. The purpose of this study was to test the hypothesis that different signaling mechanisms exist for NO-stimulated and(More)