Induction of metamorphosis in the sand dollar Peronella japonica by thyroid hormones |
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| Authors: | Minoru Saito Masanori Seki Shonan Amemiya Kyo Yamasu Takashi Suyemitsu Katsutoshi Ishihara |
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| Institution: | Department of Regulation Biology, Faculty of Science, Saitama University, Urawa, Saitama 338.;Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113, Japan. |
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| Abstract: | The larva of the sand dollar Peronella japonica lacks a mouth and gut, and undergoes metamorphosis into a juvenile sand dollar without feeding. In the present study, it was found that thyroid hormones accelerate the metamorphosis of P. japonica larvae. The contents of thyroid hormones in larvae increased gradually during development. Thiourea and potassium perchlorate, inhibitors of thyroid hormone synthesis, delayed larval metamorphosis and simultaneously repressed an increase in the content of thyroxine in the larval body. These results suggest that the P. japonica larva has a system for synthesis of thyroid hormones that act as factors for inducing metamorphosis. |
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| Keywords: | metamorphosis sand dollar sea urchin thyroid hormone |
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