Epidermal protein metabolism directed toward keratinization by hydrocortisone in the chick embryonic skin growing in a chemically defined medium☆

[摘要] Themetabolismoftheepidermalstructuralandnonstructuralproteinswasstudiedinhydrocortisone-inducedinvitrokeratinizationof13-daychickembryonicskingrowinginachemicallydefinedmedium.Theproteinmetabolismoftheepidermiswasexaminedbydeterminingtheamountsofradioactivityincorporatedintothefractionsofreduced,S-carboxymethylatedepidermalproteins(SCMEp)whichwereseparatedbypolyacrylamidegelelectrophoresis.Agroupofhighmolecularweight,glycine-richderivativesoftheepidermalfibrousproteincalledSCMEpAwerefoundtobeactivelysynthesizedinthehydrocortisone-treatedepidermisalone,whileagroupofundefinedproteinderivativescalledSCMEpXwasshowntobesynthesizedexclusivelyinthenontreatedepidermis.Chase-cultureoftheprelabeledexplantsrevealedthathydrocortisoneacceleratedthedegradationofgeneralproteinsincludingSCMEpXwhileSCMEpAremainedmetabolicallystablethroughouttheculture.ActinomycinDdidnotsignificantlyaffectthehydrocortisone-inducedsynthesisofSCMEpAbutgreatlyinhibitedthatofSCMEpXofthenontreatedepidermis,suggestingtheinductionbythesteroidofrelativelystablemRNAforSCMEpA.Fromthesefindings,itisconcludedthathydrocortisonedirectedtheculturedepidermistowardkeratinizationthroughaccelerationofthesynthesisofepidermalstructuralproteinsanddegradationofotherproteins.

[学科分类] 生物科学（综合）