Immersion as a method of thyroxine administration in amphibian metamorphosis studies☆

[摘要] Normalandhypophysectomizedtadpolesatroomtemperature(22°–25°C)weresupplieddl-thyroxineatconcentrationsof0.08–0.8μg/liter,andhypophysectomizedtadpolesina15°Cbathweresuppliedthehormoneat0.8–1.6μg/liter.Eachdaythesetadpolesweresuppliedwithfreshhormonesolution,andtheoldersolutionwassuppliedtootherhypophysectomizedtadpolesinitiallymatchedwiththefirsttadpolegroupastostageandsize.Inthe15°Cbaththetwosetsoftadpolesmetamorphosedatessentiallyidenticalrates.Atroomtemperaturetheoriginaltadpolesmetamorphosedonlyveryslightlymorerapidlythandidthosereceivingthe“used”hormonesolution.Thiswasequallytruewhethernormalorhypophysectomizedtadpoleswereemployedastheoriginalreceiversofthehormone.Theseresultsdemonstratethattadpoles,undertheconditionsoftheexperiment,eventhoughmetamorphosingrapidly,utilizeextremelylittlehormone,andthatbutlittlehormoneislostbyadsorptionontotheglasswallsoftheculturevesselsorthroughchemicalalterationinthemedium.Themethodofimmersionisthereforesatisfactoryforprovidingarelativelyunvaryingandcontinuoussourceofdl-thyroxine.

[学科分类] 生物科学（综合）