The occurrence of biochemical metamorphic events without anatomical metamorphosis in the axolotl☆☆☆

[摘要] AlthoughtheaxolotlAmbystomamexicanumisanatomicallyalarvalamphibian,itdoesproduceasmallamountofendogenousthyroxine.Accordingtothetheorythatdifferenttissueshavedifferentthresholdsofresponsetothyroxine,theaxolotlmayundergocertainbiochemicalmetamorphiceventswithoutanatomicalmetamorphosis.Gelelectrophoresisdemonstratedthatthehemoglobinandserumproteincompositionofthebloodchangedatapproximately125and210daysofnormaldevelopment,respectively.Botheventswereprematurelyinduciblebythyroxine;metamorphosedanimalshadneotenousadulthemoglobinandserumproteinelectrophoreticpatterns.Onsodiumdodecylsulfate-polyacrylamidegels,denaturedneotenousadulthemoglobinfractionatedintocomponentsof15,000and19,000,and24,500molecularweight(relativetothatofbovinehemoglobinmonomer,15,500).Larvalhemoglobinpossessedcomponentsof13,800and19,500molecularweight.Itwasconcludedthat(1)at100–150daysofnormaldevelopment,theproductionofnewhemoglobinpolypeptidesubunitswasstimulatedwhereasthesynthesisoflarvalsubunitswasinhibited,(2)theaxolotlisnotbiochemicallyneotenousforatleasttwonormallymetamorphicevents,and(3)thetissuesresponsibleforcertainbiochemicalmetamorphiceventsprobablyhavealowerthresholdofresponsetothyroxinethanthetissuesresponsibleforanatomicalmetamorphosis.

[学科分类] 生物科学（综合）