Effects of orexin A on proliferation, survival, apoptosis and differentiation of 3T3‐L1 preadipocytes into mature adipocytes

摘要

MetabolicactivitiesoforexinA(OXA)inmatureadipocytesaremediatedviaPI3K/PKBandPPARγ.However,theeffectsofOXAonpreadipocytesarelargelyunknown.WereportherethatOXAstimulatestheproliferationandviabilityof3T3‐L1preadipocytesandprotectsthemfromapoptosisviaERK1/2,butnotthroughPKB.OXAreducesproapoptoticactivityofcaspase‐3viaERK1/2.InhibitionofERK1/2preventsthedifferentiationofpreadipocytesintoadipocytes.Unlikeinsulin,neithershort‐termnorprolongedexposureof3T3‐L1preadipocytestoOXAinducespreadipocytedifferentiationtoadipocytes,despiteincreasedERK1/2phosphorylation.Unlikeinsulin,OXAfailstoactivatePKB,whichexplainsitsinabilitytoinducethedifferentiationofpreadipocytes...