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1996 Fiscal Year Final Research Report Summary

Neurosecretory cells found along the dorsal strand of ascidians

Research Project

Project/Area Number 06804052
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 生物形態・構造
Research InstitutionSaitama University

Principal Investigator

TERAKADO Kiyoshi  Saitama University, Department of Regulation Biology, Associate Professor, 理学部, 助教授 (40008834)

Project Period (FY) 1994 – 1996
KeywordsProtochordate / ascidian / neural complex / dorsal strand / GnRH neuron / pituitary hormone / hypophysis / immunocytochemistry
Research Abstract

Hypophysis, which functions to maintain the homeostasis in all vertebrate species, appears suddenly in its complete form in lower vertebrates. That is, the hypophysis is the organ unique for vertebrates and is absent in invertebrates. From a phylogenetic point of view, the possibility that any structure homologous to the vertebrate adenohypophysis may exist in protochordates has long been pointed out. In ascidians, the neural gland was considered to be homologous to the vertebrate adenohypophysis because of its morphological similarity. However, despite of recent extensive studies using various methods, the evidence that indicates its homology is very scarce.
In this research project, we obtained some important cytochemical and developmental evidences revealing the homology of asacidian dorsal strand to the vertebrate adenohypophysis. They are : (1) presence of prolactin (PRL) -immunoreactive cells along the doesal strand. The localization of the immunoreactive material in the secretory granules of these cells has been ascertained by immunoelectron microscopy. (2) presence of gonadotropin (GTH) -immunoreactive cells. (3) presence of adrenocorticotropin (ACTH) -and POMC-related beta-endorphin immunoreactive cells. In adition, numerous gonadotropin-releasing hormone (GnRH) -producing neurons are localized in the vicinity of the dorsal strand. These structures in ascidians may correspond to the hypothalamus-pituitary system of vertebrate.

  • Research Products

    (2 results)

All Other

All Publications (2 results)

  • [Publications] Terakado K.et al.: "Prolactin-like immunoreactivity in the granules of neural complex cells in the ascidian Halocynthia roretzi" Cell and Tissue Research. (in press). (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Terakado K., Ogawa M., Inoue K., Yamamoto K., Kikuyama S.: "Prolactin-like immunoreactivity in the granules of neural complex cells in the ascidian Halocynthia roretzi" Cell Tissue Res.(in press). (1997)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-03-09  

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