Induction of Metamorphosis and Thyroid Function in the Larval Lamprey
A larval lamprey undergoes metamorphosis into the adult form. This metamorphosis is remarkable and is accompanied by external changes in oral apertures, branchiopores, eyes, and other parts of the body. Simultaneously, thyroid follicles are formed from the endostyle located underneath the pharyngeal region. Up to the present, it has not been clear which hormonal or neuronal factors are involved in this metamorphosis. Recently, we observed that potassium perchlorate (KC1O4) induces metamorphosis completely within three months. In this paper, we report the results of those investigations and the plasma thyroxine (T4) level in the larvae during and after induction of metamorphosis to clarify whether or not thyroid function is involved in metamorphosis.
KeywordsMetamorphic Stage Thyroid Follicle Large Larva Roid Hormone Pharyngeal Region
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