Seeonlineversionforlegendandreferences.SnapShot:TheHormonalControlofFoodIntakeAnthonyP.Coll,GilesS.H.Yeo,I.SadafFarooqi,StephenO’RahillyInstituteofMetabolicScience,UniversityofCambridge,Cambridge,CB20QQ,UK572Cell135,October31,2008©2008ElsevierInc.DOI10.1016/j.cell.2008.10.014SnapShot:TheHormonalControlofFoodIntakeAnthonyP.Coll,GilesS.H.Yeo,I.SadafFarooqi,StephenO’RahillyInstituteofMetabolicScience,UniversityofCambridge,Cambridge,CB20QQ,UK572.e1Cell135,October31,2008©2008ElsevierInc.DOI10.1016/j.cell.2008.10.014Foodintakeisnormallymatchedwithgreatprecisiontochangingenergyrequirements.Anumberofcirculatingpeptidesandendogenouslyproducedsteroidsorchestrateappetitivebehaviorthroughtheiractionsonthehypothalamus,thebrainstem,orafferentautonomicnerves.Thesehormonescomefromatleastthreesites:fatcells,classicendocrineorgans,andthegastrointestinaltract.HypothalamicArchitectureWithinthebrain,thehypothalamusisacriticalregionthatreceivesandintegratesthesesignalsfromtheperiphery.Containedwithinthearcuatenucleusofthehypothalamusaretwopopulationsofneuronshighlyresponsivetoleptin(Cone,2005).OneexpressesPOMCandCART,theotherexpressesbothNPYandAgRP.ThePOMC-derivedmelanocortinsαandβMSHareanorexigenic(appetitesuppressing)whereasAgRPandNPYarepotentorexigens(appetitestimulating).Fromthearcuatenucleus,theseneuronsprojecttootherbrainareasthatareinvolvedinenergyhomeostasis,includingotherregionsofthehypothalamussuchasthePVN,LH,andDMN.InthefedstateanincreaseinleptinstimulatesPOMCneurons,increasingmelanocortinlevelswhileinhibitingAgRPneurons.ThisinturnincreasessignalingatMC4R,decreasingfoodintakeandincreasingenergyexpenditure.Duringfasting,adecreaseinleptininactivatesPOMCneurons(reducingmelanocortinlevels)andstimulatesAgRPexpression.Theresul-tantdecreaseinMC4Rsignalingstimulatesfeedingandreducesenergyexpenditure.Thearcuatemelanocortinsystemisalsoakeysiteofactionof5HT(Heisleretal.,2006).Notonlydoes5HTinhibitNPY/AgRPneurons,butitalsoactivatesPOMCneurons.ThePVNreceivesprojectionsfrombothPOMC...
