NeuroendocrinesystemAi-MinBao,M.D.Ph.D.ZhejiangUniversitySchoolofMedicineTheHPGaxisTheHPTaxisTheHPAaxisTheendocrinesystemdiffersfrommostoftheotherorgansystemsofthebody-thevariousglandsarenotanatomicallyconnected;however,theydoformasysteminthefunctionalsense.•Nervoussystemperformsshorttermcrisismanagement•Endocrinesystemregulateslongtermongoingmetabolic•Endocrinecommunicationiscarriedoutbyendocrinecellsreleasinghormones–Altermetabolicactivitiesoftissuesandorgans–Targetcells•ParacrinecommunicationinvolveschemicalmessengersbetweencellswithinonetissueEndocrineversusNervoussystem“Hereinthiswell-concealedspot,almosttobecoveredwithathumbnail,liestheverymainspringofprimitiveexistence–vegetative,emotional,reproductive–onwhichwithmoreorlesssuccess,manhascometosuperimposeacortexofinhibitions.”Cushing(1932)rostalcaudalBothhumanPVNandSONcontainabout50.000neurons.AlmostallvasopressinergicSONneuronsprojecttotheposteriorpituitarythusinfluencingplasmalevels.InthePVNthereare3differenttypesofvasopressinproducingneurons.SometakepartintheHPA-axis,someprojecttotheneuropituitary,sometootherbrainareas.HypothalamusParvocellularneurosecretorycell(PvC)神经内分泌小细胞–Hypophysiotrophicarea,HTA下丘脑促垂体区•调节腺垂体内分泌活动Magnocellularneurosecretorycell(MgC)神经内分泌大细胞–视上核、室旁核–神经垂体激素－催产素、血管加压素–神经垂体激素运载蛋白I,II(NeurophysinI,II)–神经肽：脑啡肽、内啡肽、神经肽YTheHypothalamus-HormonesandReleasingFactorsProlactinReleasingHormone(PRH)ProlactinInhibitingHormone(PIH)ThyrotropinReleasingHormone(TRH)CorticotropinReleasingHormone(CRH)GonadotropinReleasingHormone(GnRH)GrowthHormoneReleasingHormone(GHRH)GrowthHormoneInhibitingHormone(GHIH)促黑素细胞激素释放/抑制因子（melanophore-stimulatinghormonereleasingfactor,MRF;melanophore-stimulatinghormonerelease-inhibitingfactor,MIF)可能是催产素裂解出来的两种小分子肽Regulationofhypothalamichormones神经调节:–单胺类递质:DA,NE,5-HT–肽类物质:脑啡肽、β-内啡肽、神经降压素、P物质、VIP下级激素的反馈效应•Releases9importantpeptidehormones•All9bindtomembranereceptorsandusecyclicAMPasasecondmessenger•Anteriorpituitaryoriginatesfromepithelium;posteriorpituitaryfromneuraltissueHypophysis=pituitarySubdividedintotheparsdistalis,parsintermediaandparstuberalisTheanteriorlobe(adenohypophysis)Atthemedianeminence,neuronsreleaseregulatoryfactorsthroughfenestratedcapillaries-Releasinghormones-InhibitinghormonesThePituitaryGland-AnteriorPituitaryHormonesMSH(parsintermedia)ThePituitaryGland-AnteriorPituitaryHormonesThePituitaryGland-PosteriorPituitaryHormones•Containsaxonsofhypothalamicnerves•neuronsofthesupraopticnucleus(SON)andparaventricularnucleus(PVN)manufactureantidiuretichormone(ADH=vasopressin,AVP),oxytocin(OXT)andNeurophysin(NP)•ADHdecreasestheamountofwaterlostatthekidneys,elevatesbloodpressure•OXTstimulatescontractilecellsinmammaryglands,stimulatessmoothmusclecellsinuterusTransportation:•NP-1+OT;NP-2+VP•inaxoplasmoftheneuron’sfibersRelease:ExocytosisPosteriorPituitaryandhormonesThestructuralandchemicalcharacteristicsofAVPandOXTThecyclicalpeptidesdifferinonly2aminoacidpositionsBothcontaindisulphidebridgesbetweenCysteineresidues(半胱氨酸残基)atpositions1and6.RegulationofADHsecretion↑osmolality→↑secretionIncreasedextracellularfluidosmolarityreducessizeofosmoreceptorslocatedinhypothalamus,whichinturnstimulatesADHs...
