Biochemical studies of mammalian oogenesis: Metabolic cooperativity between granulosa cells and growing mouse oocytes☆

[摘要] Freezefractureandlanthanumtracerexperimentshaveshownthatgapjunctionsexistthroughoutfolliculogenesisbetweengranulosacellsandgrowingmouseoocytes(AndersonandAlbertini,J.CellBiol.71,680–686,1976).Thefollowinglinesofexperimentationinthepresentstudysuggestthatmetaboliccooperativityexistsbetweengranulosacellsandtheirenclosedoocytes,i.e.,gapjunctionsarefunctional,andthatinmostcasesexamined,greaterthan85%ofthemetabolitespresentinfollicle-enclosedoocyteswereoriginallytakenupbythegranulosacellsandtransferredtotheoocyteviagapjunctions:(1)Whenincubatedwithvariousradiolabeledcompounds,follicle-enclosedoocytescontainedmoreintracellularradioactivitythandidoocyteswithnoattachedgranulosacells(denudedoocytes);(2)fortworadiolabeledribonucleosidesexamined,thedistributionofphosphorylatedmetabolitesinfollicle-enclosedoocytesresembledthatofgranulosacellsanddifferedsignificantlyfromthatindenudedoocytes;(3)pulse-chaseexperimentswithradiolabeledribonucleosidesrevealedthatduringthechaseperiodmoreradioactivitybecameassociatedwiththefollicle-enclosedoocyte;(4)treatmentsknowntodisruptgapjunctionsinothercelltypeswereeffectiveinreversiblyuncouplingmetaboliccooperativitybetweengranulosacellsandoocytes;and(5)aseriesofcontrolexperimentsusing(a)mediumconditionedbygranulosacellsand(b)coculturesofdenudedoocytesandgranulosacellsinwhichphysicalcontactbetweenthetwocelltypeswasnotpermitteddemonstratedthatcontactbetweenfolliclecellsandoocyteswasnecessaryforobservingmetaboliccooperativity.Metaboliccooperativitywasalsofoundbetweenfolliclecellsandoocytesinthetwoculturesystemswhichsupportgrowthofmouseoocytesinvitro.Thefactthatoocytesdonotgrowwell,ifatall,intheabsenceoffolliclecellsandthelargecontributionofnutrientsapparentlyfurnishedtotheoocytebythegranulosacellsisconsistentwiththeconceptthatgapjunctionmediatedmetaboliccooperativitybetweenfolliclecellsandtheirenclosedoocytesisvitalformammalianoocytegrowth.

[学科分类] 生物科学（综合）