Description | SitagliptinisapotentinhibitorofDPP4withIC50of19nMinCaco-2cellextracts. |
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IC50&Target | IC50:19nM(DPP4) |
InVitro | SitagliptinphosphateexhibitsapotentinhibitoryeffectonDPP-4withIC50of19nMfromCaco-2cellextracts[1]. SitagliptinreducesinvitromigrationofisolatedsplenicCD4T-cellsthroughapathwayinvolvingcAMP/PKA/Rac1activation[2]. Stagliptinexertsanovel,directactioninordertostimulateGLP-1secretionbytheintestinalLcellthroughaDPP-4-independent,proteinkinaseA-andMEK-ERK1/2-dependentpathway.Itreducestheeffectofautoimmunityongraftsurvival[3]. |
InVivo | Invivo,theED50valueofsitagliptinphosphateforinhibitionofplasmaDPP-4activityiscalculatedtobe2.3mg/kg7hourpostdoseand30mg/kg24hourpostdoseinfreelyfedHan-Wistarrats[1]. Thestreptozotocin-inducedtype1diabetesmousemodelexhibitselevatedDPP-4levelsintheplasmathatcanbesubstantiallyinhibitedinmiceonanSitagliptinphosphatediet.Thisisachievedbyapositiveeffectontheregulationofhyperglycemia,potentiallythroughprolongationofisletgraftsurvival[4]. TheplasmaclearanceandvolumeofdistributionofSitagliptinphosphatearehigherinrats(40-48mL/min/kg,7-9L/kg)thanindogs(9mL/min/kg,3L/kg);anditshalf-lifeisshorterinrats,2hourscomparedwith4hoursindogs[5]. |
ClinicalTrial | ViewMoreCollapse |
References |
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KinaseAssay [1] | DPP-4isextractedfromconfluentCaco-2cells.After5minutesofincubationatroomtemperaturewithlysisbuffer(10mMTris-HCl,150mMNaCl,0.04U/mLaprotinin,0.5%NonidetP40,pH8.0),cellsarecentrifugedat35,000gat4°Cfor30minutes,andthesupernatantisstoredat-80°C.Assaysareperformedbymixing20μLofappropriatecompounddilutionswith50μLofthesubstratefortheDPP-4enzyme,H-Ala-Pro-7-amido-4-trifluoromethylcoumarin(finalconcentrationintheassay,100μM)and30μLoftheCaco-2cellextract(diluted1000-foldwith100mMTris-HCl,100mMNaCl,pH7.8).Platesareincubatedatroomtemperaturefor1hour,andfluorescenceismeasuredatexcitation/emissionwavelengthsof405/535nmusingaSpectraMaxGeminiXS.DissociationkineticsofinhibitorsfromtheDPP-4enzymeisdeterminedaftera1-hourpreincubationofCaco-2cellextractswithhighinhibitorconcentrations(30nMforBI1356,3μMforvildagliptin).TheenzymaticreactionisstartedbyaddingthesubstrateH-Ala-Pro-7-amido-4-trifluoromethylcoumarinaftera3000-folddilutionofthepreincubationmixturewithassaybuffer.Undertheseconditions,thedifferenceinDPP-4activityatacertaintimepointinthepresenceorabsenceofaninhibitorreflectstheamountofthisinhibitorstillboundtotheDPP-4enzyme.Maximalreactionrates(fluorescenceunits/seconds×1000)at10-minuteintervalsarecalculatedusingtheSoftMaxsoftwareoftheSpectraMaxandcorrectedfortherateofanuninhibitedreaction[(vcontrol-vinhibitor)/vcontrol].MCEhasnotindependentlyconfirmedtheaccuracyofthesemethods.Theyareforreferenceonly. | ||||||||||||||||||||||||||||
CellAssay [2] | CD4T-cellsareplatedonmembraneinsertsinserum-freeRPMI1640,andcellmigrationisassayedusingTranswellchambers(Corning),inthepresenceorabsenceofpurifiedporcinekidneyDPP-4(32.1units/mg;100mU/mLfinalconcentration)andDPP-4inhibitor(100μM).After1hour,cellsontheuppersurfaceareremovedmechanically,andcellsthathavemigratedintothelowercompartmentarecounted.Theextentofmigrationisexpressedrelativetothecontrolsample.MCEhasnotindependentlyconfirmedtheaccuracyofthesemethods.Theyareforreferenceonly. AnimalAdmiNISTration | [1] Sitagliptinisformulatedin0.5%aqueoushyroxyethylcellulose. OvernightfastedC57BL/6Jmicearechallenged45minaftercompoundadministrationwithanoralglucoseload(2g/kg).Bloodsamplesforglucosemeasurementareobtainedbytailbleedpredoseandatserialtimepointsaftertheglucoseload.Toevaluatethedurationoftheeffectonglucosetolerance,vehicleorDPP-4inhibitorsareadministered16hbeforetheglucosechallenge.MCEhasnotindependentlyconfirmedtheaccuracyofthesemethods.Theyareforreferenceonly. References |
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