Objective:To investigate the significance of inhibin A(INH A)in the in vitromaturation.Methods:All oocytes extracted were divided into PMSG group(mice’s peritoneal cavity was injected with PMSG(pregnant mare serum gonadotrophin)before getting oocytes) and none PMSG group.The germinal vesicle(GV)oocytes isolated from rats were cultured in the INH A solutions at concentrations of 0(control)

50

100

200 and 350 ng/ml IVF plus culture media.Extrusion of the first polar body(PB1)and staining of cortical granules(CG)were observed.Results:We can go(t17.2±2.6)oocytes/mice with using PMSG

and we can got(15.9±1.8)oocytes/mice without PMSG(P>0.05).There was no difference in the rate of PB1 between PMSG group and none PMSG group.In PMSG group

INH A solutions at concentrations of 200 ng/ml

350 ng/ml had higer rate of PB1 than that in control group(P<0.05);In the none PMSG group

each INH A group had no significant difference in the rate of PB1.Conclusion:INH A and PMSG maybe played an important role in oocytes maturation from GV phase in vitro.