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1、Neuroendocrine system Neuroendocrine system The HPG axisThe HPT axisThe HPA axisThe endocrine system differs from most of the other organ systems of the body -the various glands are not anatomically connected;however,they do form a system in the functional sense.The HPG axisThe HPT axisThe HPNervous

2、 system performs short term crisis managementEndocrine system regulates long term ongoing metabolic Endocrine communication is carried out by endocrine cells releasing hormonesAlter metabolic activities of tissues and organs Target cellsParacrine communication involves chemical messengers between ce

3、lls within one tissueEndocrine versus Nervous systemNervous system performs short“Here in this well-concealed spot,almost to be covered with a thumbnail,lies the very main spring of primitive existence vegetative,emotional,reproductive on which with more or less success,man has come to superimpose a

4、 cortex of inhibitions.”Cushing(1932)“Here in this well-concealed srostal caudalrostal caudalBoth human PVN and SON contain about 50.000 neurons.Almost all vasopressinergic SON neurons project to the posterior pituitary thus influencing plasma levels.In the PVN there are 3 different types of vasopre

5、ssin producing neurons.Some take part in the HPA-axis,some project to the neuropituitary,some to other brain areas.Both human PVN and SON containHypothalamusParvocellular neurosecretory cell(PvC)神經(jīng)內(nèi)分泌小細胞 Hypophysiotrophic area,HTA下丘腦促垂體區(qū) 調(diào)節(jié)腺垂體內(nèi)分泌活動Magnocellular neurosecretory cell(MgC)神經(jīng)內(nèi)分泌大細胞 視上核、室

6、旁核 神經(jīng)垂體激素催產(chǎn)素、血管加壓素 神經(jīng)垂體激素運載蛋白I,II(Neurophysin I,II)神經(jīng)肽：腦啡肽、內(nèi)啡肽、神經(jīng)肽YHypothalamusParvocellular neurThe Hypothalamus-Hormones and Releasing FactorsProlactin Releasing Hormone(PRH)Prolactin Inhibiting Hormone(PIH)Thyrotropin Releasing Hormone(TRH)Corticotropin Releasing Hormone(CRH)Gonadotropin Releasin

7、g Hormone(GnRH)Growth Hormone Releasing Hormone(GHRH)Growth Hormone Inhibiting Hormone(GHIH)促黑素細胞激素釋放促黑素細胞激素釋放/抑制因子抑制因子（melanophore-stimulating hormone releasing factor,MRF;melanophore-stimulating hormone release-inhibiting factor,MIF)可能是可能是催產(chǎn)素催產(chǎn)素裂解出來的兩裂解出來的兩種小分子肽種小分子肽The Hypothalamus-Hormones anReg

8、ulation of hypothalamic hormones神經(jīng)調(diào)節(jié)神經(jīng)調(diào)節(jié):單胺類遞質(zhì):DA,NE,5-HT 肽類物質(zhì):腦啡肽、-內(nèi)啡肽、神經(jīng)降壓素、P物質(zhì)、VIP下級激素的反饋效應下級激素的反饋效應Regulation of hypothalamic horReleases 9 important peptide hormonesAll 9 bind to membrane receptors and use cyclic AMP as a second messengerAnterior pituitary originates from epithelium;posterior p

9、ituitary from neural tissueHypophysis=pituitaryReleases 9 important peptide hSubdivided into the pars distalis,pars intermedia and pars tuberalisThe anterior lobe(adenohypophysis)At the median eminence,neurons release regulatory factors through fenestrated capillaries-Releasing hormones-Inhibiting h

10、ormonesSubdivided into the pars distaThe Pituitary Gland-Anterior Pituitary HormonesMSH(pars intermedia)The Pituitary Gland-AnteriorThe Pituitary Gland-Anterior Pituitary Hormones The Pituitary Gland-AnteriorThe Pituitary Gland-Posterior Pituitary HormonesThe Pituitary Gland-PosterioContains axons o

11、f hypothalamic nervesneurons of the supraoptic nucleus(SON)and paraventricular nucleus(PVN)manufacture antidiuretic hormone(ADH=vasopressin,AVP),oxytocin(OXT)and Neurophysin(NP)ADH decreases the amount of water lost at the kidneys,elevates blood pressureOXT stimulates contractile cells in mammary gl

12、ands,stimulates smooth muscle cells in uterusTransportation:NP-1+OT;NP-2+VPin axoplasm of the neurons fibersRelease:ExocytosisPosterior Pituitary and hormones Contains axons of hypothalamicThe structural and chemical characteristics of AVP and OXT The cyclical peptides differ in only 2 amino acid po

13、sitions Both contain disulphide bridges between Cysteine residues(半胱氨酸殘基)at positions 1 and 6.The structural and chemical chRegulation of ADH secretionosmolality secretionIncreased extracellular fluid osmolarity reduces size of osmoreceptors located in hypothalamus,which in turn stimulates ADH secre

14、tion blood volume secretionADH release is also controlled by cardiovascular reflexes in response to blood volume(atrial receptors)/pressure changesRegulation of ADH secretionosOXTSynthesis:SON,PVNSecretion:Parturition,lactation,coitionFunction:-Contraction of the uterus*induces labor contraction*red

15、uces postpartum bleeding-Contraction of myoepithelial cells in the breast stimulates milk let-downRegulation-Neuroendocrine reflex(Milk ejection reflex)*Suckling-Positive feedback-Acute stress(-)OTX secretion*Levels of sex steroidsOXTSynthesis:SON,PVN神經(jīng)生物學-下丘腦與垂體的內(nèi)分泌功能課件Review:Regulation by Negative

16、 FeedbackReview:Regulation by Negative神經(jīng)生物學-下丘腦與垂體的內(nèi)分泌功能課件Hormone Effects on Gene ActivityHormone Effects on Gene ActiviThree Methods of Hypothalamic Control over the Endocrine SystemThree Methods of Hypothalamic Thyroid stimulating hormone(TSH)Triggers the release of thyroid hormonesThyrotropin rel

17、easing hormone promotes the release of TSHAdrenocorticotropic hormone(ACTH)Stimulates the release of glucocorticoids by the adrenal glandCorticotrophin releasing hormone causes the secretion of ACTHFollicle stimulating hormone(FSH)Stimulates follicle development and estrogen secretion in females and

18、 sperm production in malesLeutinizing hormone(LH)Causes ovulation and progestin production in females and androgen production in malesGonadotropin releasing hormone(GnRH)promotes the secretion of FSH and LHHormones of the adenohypophysisThyroid stimulating hormone(TProlactin(PRL)Stimulates the devel

19、opment of mammary glands and milk productionGrowth hormone(GH or somatotropin)Stimulates cell growth and replication through release of somatomedins or IGFGrowth-hormone releasing hormone(GH-RH)Growth-hormone inhibiting hormone(GH-IH)Hormones of the adenohypophysisProlactin(PRL)Hormones of theMelano

20、cyte-stimulating hormone(MSH)May be secreted by the pars intermedia during fetal development,early childhood,pregnancy or certain diseasesStimulates melanocytes to produce melaninTypes -MSH,-MSH（人）,-MSHEffect 黑素細胞(melanophores)黑色素生成，使黑色素顆粒在細胞內(nèi)分散 可能參與調(diào)節(jié)GH、醛固酮、CRH、胰島素、LH等分泌Regulation MIF MRFMelanocyte

21、-stimulating hormonePro-opiomelanocortin(POMC,阿黑皮素原阿黑皮素原)a precursor hormone with 241 amino acid residues from corticotrophs in anterior pituitary,also synthesized by other tissues,e.g.placenta,GIprecursor for ACTH,-lipotropin(-LPH),-lipotropin(-LPH),-endorphin,N-terminal peptide,MSH(-MSH within ACT

22、H,-MSH within-LPH,and-MSH within N-Peptide)Pro-opiomelanocortin(POMC,阿黑皮Pro-opiomelanocortin(POMC)-a precursor polypeptide,synthesized from the 285-aa polypeptide precursor,pre-pro-opiomelanocortin(pre-POMC),by the removal of a 44-aa signal peptide sequence during translation.Pro-opiomelanocortin(POMC)-