Characterization and regulation of insulin binding by embryonic chick heart cells☆
[摘要] Wehavecomparedinsulinbindingbyheartcellsat7and14daysofdevelopment.Speciesspecificity,optimumpH,temperaturerelationships,andtimetoequilibriumforbindingofinsulinwerethesameinboth7and14-daysystems.CurvilinearScatchardplotsforchickeninsulinbindingweredemonstrated.Bindingaffinitiesandcapacitieswerecalculatedbasedonatwo-receptormodelincludingaspecifichigh-affinityreceptorandalessspecificlow-affinityreceptorthatboundinsulinandothergrowthpeptides.Apparentassociationconstants(KA)were4.0and0.05nM−1andbindingcapacitieswere600and9000sitespercellforhigh-andlowaffinityreceptors,respectively.Wehavealsoinvestigatedtheabilityofinsulintoregulatebindingtoitsownreceptors.Chickheartcellsfrom7-and14-dayembryos,culturedfor44hrininsulin-enrichedmedium(3.4μM),bound50%lessinsulin(down-regulated)thancontrolcells.Atbothdevelopmentalstages,downregulationwasprimarilyareductioninbindingtothehigh-affinityreceptor.Thelow-affinityreceptorwaslesssusceptibletodownregulationandretaineditsabilitytomediatemaximalinsulinstimulationofaminoacidtransport.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
