Abstract: Objective To investigate the effect of nitric oxide(NO) ,we observed the influence of different doses of Sodium nitroprusside and NW-nitro-L-arginine methyl ester(l-NAME) on maturation of germinal vesicle stage oocyte in vitro. Methods We used exogenous PMSG to induce mouse superovulate. took out of hibateral ovaries. This research Used mouse oocyte culture model, devided into L-NAMEgroup、SNP+dbcAMP+L-NAMEgroup 、P+dbcAMP+SNP+L-NAMEgroup. oocyte maturation rate（GVBDpercentage、PB1rate） was examined under microscop.Results Compared with dbcAMP (28±0.2,11.1±0.7) group, the SNP+dbcAMPgroup GVBD percentage and PB1 rate(52.5±0.4and32.5±0.1)significantly increased (P<0.05), Compared with P+dbcAMP + SNPgroup(90.1±1.3and 66.6±0.9), the P+ dbcAMP +SNP +L-NAME group oocyte GVBD percentage and PB1 rate（62.8±0.3and20±1.4) significantly decreased(P<0.05).Conclusion When dbcAMP and L-NAME suppress mouse oocyte maturation,Low concentration of NO show promoting effect , Progesterone（P） can enforce this promoting effect.

Key words: nitric oxide, oocyte, L-NAME, dbcAMP, progesterone。