Hormonal effects on RNA synthesis by stage 6 oocytes of Xenopus laevis☆

[摘要] RNAsynthesishasbeenstudiedin“large”oocytesofXenopuslaevis,bothasafunctionoftimeafterinjectionoffemaleswithhumanchorionicgonadotropin(HCG)andinrelationtotheinductionofmaturationwithprogesteroneinvitro.RatesofRNAsynthesisweremeasuredbyanalyzingthekineticsofincorporationofexogenous[3H]guanosine,andmicroinjected[3H]-or[14C]GTP,intoacid-precipitablematerial,coupledwithmeasurementsofprecursorpoolspecificactivity.ThekineticsofincorporationintoRNAofinjectedprecursorarebiphasic,indicatingthesynthesisofbothstableandunstableRNAspecies.Estimatesofthetotalrateofsynthesis(stableandunstable)werederivedfromfittingalinearfunctiontodataoverthefirst60–90min,whilealinearfunctionfittothedatabeyond90minrepresentedlargelythesynthesisofstableRNAspecies.Exposureofoocytestoprogesteronehadnoeffectoninitialsyntheticrates,butmaturingoocytessynthesizedstableRNAat1.4–1.6timestherateincontroloocytes.Acomparisonofdataobtainedwithoocytesfromunstimulated(nopriorHCGtreatment)andHCG-stimulatedfemalesindicatedthatHCGhasnosubstantialeffectonratesofRNAsynthesis.ThesignificanceofcontinuedRNAsynthesisinlargefullgrownoocytesisdiscussed.

[学科分类] 生物科学（综合）