Synthesis of serum proteins by cultures of chick embryo yolk sac endodermal cells☆

摘要

Endodermalcellswereisolatedfromyolksacsof3-daychickembryosandculturedfor6daysinEagle'sminimalessentialmediaplus10%fetalcalfserum.DuringthisperiodcellsrapidlylosttheirabilitytosynthesizeDNAasjudgedby[3H]thymidineincorporationintoDNA.InspiteofthislossofDNAsynthesisserumproteinsynthesisandsecretionremainedataconstant45%oftotalproteinsynthesisandsecretion.Thiswasdeterminedbyimmunoprecipitationofculturemediausingantibodiesdirectedagainstembryonicchickserumproteins.Mediawerealsoanalyzedforthesynthesisandsecretionofspecificserumproteinsusingpolyacrylamidegelelectrophoresis.Therelativesynthesisandsecretionoftheindividualserumproteinsfollowedthatpreviouslyobservedinovowiththeexceptionof?±-globulin-awhichbecameundetectable.Whenculturemediaweresupplementedwithovalbuminorinsulintherelativesynthesisandsecretionofcertinspecificserumproteinswerealtered.However,analysisofthesesamemediasamplesshowedthatthetotalamountsofserumproteinsynthesisandsecretionwereunaffected.