The specificity of epidermal chalone action: The results of in vivo experimentation with two purified skin extracts

[摘要] Todatetwoinhibitorsofepidermalcellproliferationhavebeencharacterized:(1)afactorwhichdepressesDNAsynthesis,and(2)afactorwhichdepressesmitoticrate.IntheabsenceofexperimentalproofithasbeenassumedthattherespectivetargetsforthesepurifiedinhibitoryfactorsareinG1andG2phasesofthecellcycle.Intheexperimentsreportedhereboththesefractionsweresubjectedtocellcyclephasespecificitytestsinordertoverifytheseassumptions.Inaddition,anepidermallyderived“cellline”(thesebaceousgland)andtwononectodermaltissueswereexaminedforaresponse.TheresultssuggestthattheresponseinducedbytheinhibitorofDNAsynthesisiscellcyclephase-specific,thatthetargetcellsareattheG1-Sphaseboundary,andthatonlyepidermalcellsrespond.SimilarlythefactorwhichdepressestheflowofcellsfromG2intomitosishadnomeasurableeffectonDNAsynthesisbyanyofthetissuestested.TheG2inhibitorlacksaninhibitoryeffectonmitosisinthesebaceousgland.Thephysiologicalroleswhichepidermalchalonesmayplayarebrieflydiscussed.ItissuggestedthataG1–G2chalonesystemmayhavebeeneffectiveinisolatingkineticallycellpopulationswithmodifiedfunctionduringtheevolutionarydevelopmentinthevertebrates.

[学科分类] 生物科学（综合）