1995 Fiscal Year Final Research Report Summary
Adult Rudiment Formation and Thyroid Hormones in Sea Urchin Larvae
| Project/Area Number |
06680715
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Developmental biology
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| Research Institution | Saitama University |
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Principal Investigator |
ISHIHARA Katsutoshi Saitama Univ.Fac.Sci.Professor, 理学部, 教授 (10008807)
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| Co-Investigator(Kenkyū-buntansha) |
SUYEMITSU Takashi Saitama Univ.Fac.Sci.Professor, 理学部, 助教授 (40092019)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Sea Urchin / H.leucospilota / A.pectinifera / Thyroid hormones / Adult Rudiment / Larval Degeneration |
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| Research Abstract |
We ahve investigated the effect of thyroid hormones (T4 and T3) on development of sea urchins Hemicentrotus pulcherrimus, Pseudocentrotus depressus, Anthocidaris crassispina and Peronera japonica. Subsequently, we studied the effect of the hormones on the other species of Echinodermates.
Thyroid hormones accelerated the development of Perona japonica and the contents of the hormones increased following the development and reached maximum just before metamorphosis. However, inhibitors such as thiourea and potassium perchlorate kept the low level of the hormone contents even before metamorphosis and prolonged the duration to metamorphosis, indicating that larvae synthesize the houmones within the larval body by taking up iodine from sea water and regulate own development.
The effect of the hormones studied on development of Holothuria leucospilota which has long period of auricularia larva and short doliolaria larva. Thyroid hormones induced degeneration of auricularia larva and the effect was especially significant in later stage of development. However, the hormones had no effect on development of Asterina pectinifera and the level of hormone content was very low throughout the development of embryos and larvae.
These results show the significance of phylogenetic investigation for the distribution of thyroid hormones in Echinodermates.
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