Aim:Protein kinase C(PKC)is as a family of serine/threonine kinases that can beactivated by Ca~(2+),phospholipid and diacylglycerol.PKC plays an important rolein oocyte maturation and activation.This study was undertaken to investigateclassical PKC(cPKC)in human oocyte maturation and activation.Methods:Ger-minal vesicle(GV)and metaphase Ⅱ(MⅡ)stage oocytes were collected fromhealthy women.The expression and distribution of cPKC were investigated byimmunoflourescence.MⅡ oocytes were treated with PKC activator or inhibitorand imaged using a laser confocal scanning microscope(LCSM).Results:In GVoocytes,PKC α,β1 and γ were localized to the germinal vesicles,with a weakexpression in ooplasm.In MⅡ oocytes,PKCα,β1 and γ were distributed evenly inooplasm.After treatment with PKC activator,phorbol 12-myristate 13-acetate(PMA),cPKC translocated to the periphery of oocyte,and cortical granules(CG)exocytosis was found.When the oocytes were treated with PKC inhibitor,staurosporine,no translocation of cPKC and CG exocytosis were found.Conclusion:PKCα,β1 and γ exist in human oocytes and activation of these sub-units could induce CG exocytosis in MⅡ stage. Aim: Protein kinase C (PKC) is a family of serine / threonine kinases that can be activated by Ca ~ (2 +), phospholipid and diacylglycerol. PKC plays an important role in oocyte maturation and activation. This study was undertaken to investigate classical PKC cPKC) in human oocyte maturation and activation. Methods: Ger-minal vesicle (GV) and metaphase II (MII) stage oocytes were collected from healthy women. The expression and distribution of cPKC were investigated by immunoflourescence. MII oocytes were treated with PKC activator or inhibitorand Imagesd using a laser confocal scanning microscope (LCSM). Results: In GVoocytes, PKC α, β1 and γ were localized to the germinal vesicles, with a weakexpression in ooplasm. MII oocytes, PKCα, β1 and γ were distributed evenly inooplasm. After treatment with PKC activator, phorbol 12-myristate 13-acetate (PMA), cPKC translocated to the periphery of oocyte, and cortical granules (CG) exocytosis was found. The oocytes were treated with PKC inhibitor, staurosporine, no t ranslocation of cPKC and CG exocytosis were found. Conlusion: PKCα, β1 and γ exist in human oocytes and activation of these sub-units could induce CG exocytosis in MⅡ stage.