Evidence for a direct effect of temperature and thyroid hormone on myelinogenesis in vitro☆

[摘要] Theeffectofthyroxineonmyelinogenesisinvitroofcerebellaobtainedfromnewbornratsandmicewastested.CerebellawereexplantedandmaintainedintissuecultureunderstandardconditionsdescribedbyBornsteinandMurray(1958)andBungeetal.(1962).Thyroxinewasaddedtotheculturemediuminconcentrationsof1.5–3μgpermilliliteroffeed.Culturesweremaintainedat36°C,32°C,and30°C,respectively.Themostconsistenteffectobservedwasaccelerationofmyelinogenesisinthepresenceofthyroxineinculturesgrownatoptimumtemperatures.Inculturesmaintainedatreducedtemperatures,thedifferentiationofcellsintoneuronsandglialelementswasdelayed,buteventuallytookplace.Myelinformationwas,however,almostcompletelysuppressed.Thepresenceofthyroxineinculturesgrownatlowtemperaturesincreasedtheincidenceofmyelinogenesis,buttheamountformedwassmallerthanthatobtainedincontrolculturesgrownatoptimaltemperature.Shiftingculturesfromlowtooptimumtemperatureresultedinquickrecoveryofmyelinogenesis.Maintenanceofmyelininfullydifferentiatedcultureswasseverelyinhibitedinthyroxine-supplementedmedium,thatwasnotrenewedseveraltimesduringa12-dayperiod.Theseobservationsareinterpretedassuggestingthatoneofthestimuliformyelinogenesismaybeametabolicsignal,mediatedprobablyviaenzymessensitivetothyroidhormonefortheirrateofsynthesis.

[学科分类] 生物科学（综合）