Inhibition of [3H]vitellogenin uptake by isolated amphibian oocytes injected with cytoplasm from progesterone-treated mature oocytes☆

[摘要] Fullygrownmeioticallyimmature(germinalvesiclestage)amphibianoocytesincorporateradioactiveprotein([3H]vitellogenin)followinginvitroculture.Invitroexposureofsuchoocytestoexogenousprogesteroneinducesgerminalvesiclebreakdownandinhibitsincorporationofvitellogenin.Inthepresentstudies,wehaveinvestigatedtheeffectsofcytoplasmtakenfrommatureandimmatureoocytesonincorporationofvitellogeninandnuclearbreakdownfollowingmicroinjectionofthismaterialintoimmatureoocytes.Vitellogeninincorporationwasmarkedlysuppressedinoocyteswhichunderwentnuclearbreakdownfollowinginjectionwithcytoplasmfrommatureoocytes.Incorporationofvitellogeninintooocyteswhichdidnotmatureafterinjectionwithcytoplasmtakenfrommatureoocytesresembledthatseeninoocytesinjectedwithimmaturecytoplasm.Thedegreeofsuppressionofvitellogeninincorporationfollowingcytoplasmicinjectionswassimilartothatseeninuninjectedoocytestreatedwithprogesterone.Oocytesinjectedwithcytoplasmobtainedfromimmatureoocytesdidnotundergoeithernuclearbreakdownorchangesinvitellogeninincorporation.Theresultssuggestthatcytoplasmobtainedfrommatureoocytescontainsafactor(s)whichaltersdirectlyorindirectlythecapacityoftheoocytecellmembranetoincorporatevitellogenin.Enucleatedimmatureoocytesalsoincorporated[3H]vitellogenin,andinjectionofsuchoocyteswithmature,butnotimmature,oocytecytoplasmsuppressedvitellogeninincorporation.Suppressiveeffectsofinjectedcytoplasmthusappeartobemediatedthroughphysiologicalchangesintherecipientoocytecytoplasmratherthanthenuclearcomponent.

[学科分类] 生物科学（综合）