Mouse Oocyte Mitogenic Activity Is Developmentally Coordinated throughout Folliculogenesis and Meiotic Maturation

Developmental Biology

Lesley J. Ritter¹  Robert B. Gilchrist¹  David T. Armstrong¹ 

[1] The Reproductive Medicine Unit, Department of Obstetrics and Gynaecology, Adelaide University, The Queen Elizabeth Hospital, 5011, Adelaide, Australia

关键词: oocyte mitogen;    oocyte meiotic competence;    folliculogenesis;    granulosa cell;    oocyte maturation;   

DOI  :  10.1006/dbio.2001.0451

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

Oocytessecretesolublefactorsthatregulatethegrowthanddifferentiationoffollicularcells,includingmaintenanceofthedistinctivecumuluscellphenotype.Thisstudydetermineswhetherthemitogenicactivityofoocytesisdevelopmentallyregulatedandexaminestheresponsivenessoffollicularcellstooocytesatdifferentstagesoffolliculardevelopment.PrepubertalSV129miceofvaryingageswereprimedwith5IUequinechorionicgonadotropin(eCG)andoocytes/zygotescollectedeither46hpost-eCG(immatureoocytes),12hafteradministrationof5IUhumanCG(hCG;ovulatedova),or12hpost-hCGandmating(zygotes).Muralgranulosacells(MGC)fromantralfolliclesandGCfrompreantralfollicleswerecultured±denudedoocytes(DO)for18h,followedbya6-hpulseof[3H]thymidineasanindicatorofcellularDNAsynthesis.CoculturingMGCwithmeioticallymaturingoocytesledtoadose-dependentincreasein[3H]thymidineincorporation(20-foldabovecontrollevelsat0.5DO/μl).However,[3H]countsremainedunchangedfromcontrollevelswhenculturedwithmeioticallyincompetentDOfrom11-to15-day-oldmice(3%germinalvesiclebreakdown;GVB),irrespectiveofdoseofDOordevelopmentalstatusofGC(MGCorpreantralGC).Insometreatments,spontaneousmeioticresumptionofcompetentoocyteswaspreventedbyculturingwith5μMmilrinone,aselectiveinhibitorofoocyte-specificcyclicnucleotidephosphodiesterase.Themitogeniccapacityofoocyteswasfoundtodeclineduringandafteroocytematuration.[3H]ThymidineincorporationinMGCwashighest(11-foldabovecontrols)whenculturedwithmeioticallyinhibited(milrinone-treated)GVDO,stimulated5.5-foldbyculturewithmaturingoocytes,3-foldwithovulatedova,andunstimulatedbyzygotes.[3H]ThymidineincorporationinMGCwasnotalteredbythedoseofmilrinone,eitherinthepresenceorabsenceofDO.MetaphaseImarkedthebeginningofthedeclineinthecapacityofoocytestopromoteMGCDNAsynthesis.Theseresultsdemonstratethatthecapacityofoocytestopromoteproliferationofgranulosacellsfollowsadevelopmentalprogram,closelylinkedtooocytemeioticstatus,increasingwiththeacquisitionofmeioticcompetenceanddecliningduringandafteroocytematuration.

【 授权许可】

Unknown