胰岛素抵抗与多囊卵巢综合征胰岛素抵抗与多囊卵巢综合征北京大学深圳医院生殖医学中心李蓉1921年，Achard和Their首先发现糖代谢异常与高雄激素血症有关;1935年，SteinandLeventhal首先提出PCOS;1976年，Kahn和同事发现高雄激素血症、胰岛素抵抗和黑棘皮症有关;1980年，Burghen首先提出PCOS与高雄激素血症、高胰岛素血症有关;背景Figure2.Sectionofapolycysticovarywithmultiplesubscapularfollicularcystsandstromalhypertrophy(leftpanel).Athigherpower(x100)islandsofluteinizedthecacellsarevisibleinthestroma(rightpanel).Thismorphologicalchangeiscalledstromalhyperthecosisandappearstobedirectlycorrelatedwithcirculatinginsulinlevels.一、胰岛素与卵巢功能的关系胰岛素通过IGF-1受体刺激卵巢分泌雌激素，雄激素及孕酮(细胞色素p-450c17α17α-羟化酶)胰岛素抑制肝脏分泌SHBG雄激素的效应胰岛素抑制肝脏合成IGFBP-1IGF-1的效应同Gn相互作用抑制卵泡的凋亡闭锁上调IGF-1受体Figure1.PossibleMechanismsofInsulinStimulationofOvarianCytochromeP450c17ActivityandAndrogenproduction.Inthecacells,insulinmaydirectlystimulate(plussigns)ovariancytochromeP450c17,resultinginincreased17-hydroxylaseand,toalesserextent,17,20-lyaseactivity.Thiswouldleadtoincreasedproductionofandrostenedione,whichisthenconvertedtotestosteronebytheenzyme17-reductase.Alternativelyorinconjunctionwiththis,insulinmaystimulateovarianandrogenproductionindirectlybyenhancingtheamplitudeofserumluteinizinghormone(LH)pulses,andluteinizinghormonemaythenstimulateovariancytochromeP450c17activity.二、胰岛素抵抗与PCOS胰岛素及其受体的结构胰岛素及其受体的结构胰岛素是胰腺Langerhans小岛上的β-细胞产生多肽，由A链(21AAs)和B链(30AAs)构成。胰岛素受体由两个α-亚单位（135kDa）和两个β-亚单位(95kDa)构成的异构四聚体。α-亚单位：存在于细胞膜外，富含半胱氨酸，是胰岛素的结合位点；β-亚单位：三种类型：细胞膜外、细胞膜、细胞浆内，后者含有ATP结合位点和几个酪氨酸自动磷酸化位点。胰岛素的作用机理（胰岛素的作用机理（11））胰岛素受体β-亚单位的酪氨酸位点磷酸化胰岛素胰岛素受体α-亚单位获得激酶活性，细胞内蛋白磷酸化胰岛素受体底物（IRS）突变胰岛素抵抗基因OGTTPCOS高胰岛素血症FIG1.TheIRisaheterotetramerconsistingoftwoa,b-dimerslinkedbydisulfidebonds.Thea-subunitcontainstheligand-bindingsite,andtheb-subunitcontainsaligand-activatedtyrosinekinase.Tyrosineautophosphorylationincreasesthereceptor’styrosinekinaseactivitywhereasserinephosphorylationinhibitsit.胰岛素的作用机理（胰岛素的作用机理（22））胰岛素抵抗的机理胰岛素抵抗的机理(1)(1)受体与胰岛素的结合或者受体亲和力无改变50%PCOS-ser:IR酪氨酸磷酸化或IR丝氨酸磷酸化50%PCOS-nl:IR下游信号传导受阻(IRS-1的磷酸化；PI3-K的活性）Figure9.Thetyrosine-phosphorylatedIRphosphorylatesintracellularsubstrates,suchasIRsubstrate(IRS)-1andIRS-2,initiatingsignaltransductionandtheplieotropicactionsofinsulin.TheactivationofPI3-K(PI3-kinase)bytyrosine-phosphorylatedIRS-1appearstobethepathwayforinsulin-mediatedglucosetransport.TheRas-MAPkinasepathwayappearstoregulatecellgrowthandglycogensynthesis.胰岛素抵抗的机理（胰岛素抵抗的机理（22））IR丝氨酸磷酸化因子IR酪氨酸激酶抑制因子膜糖蛋白PC-1/TNF-a胰岛素抵抗的机理（胰岛素抵抗的机理（33））抑制IR酪氨酸激酶活性Figure14.Insulinresistancein50%ofPCOSwomenappearstobesecondarytoacellmembrane-associatedfactor,presumablyaserine/threoninekinase,thatserine-phosphorylatestheIR-inhibitingsignaling.SerinephosphorylationofIRS-1appearstobethemechanismforTNF-mediatedinsulinresistance.ThemembraneglycoproteinPC-1alsoinhibitsIRkinasea...
