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Endocrine cells in the gut of the ascidian Styela clava


Ultrastructural studies have shown the presence of two types of granulated endocrine cell in the gut of Styela clava. Type I, which occurs in the stomach and intestine contains small irregular granules, each with a distinct halo. Type II, found only in the oesophagus contains larger rounded granules, often with little or no halo. The characteristics of these two cell types are compared with those of endocrine cells found in the digestive tracts of other protochordates and discussed with special reference to the evolution of gastrointestinal endocrine cells in vertebrates.

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Correspondence to Dr. M. C. Thorndyke.

Additional information

The authors are grateful to Mr. R. Jones for photographic assistance. Animals were collected by courtesy of the Admiralty Marine Trials Station, Portsmouth, This research was carried out during the tenure of S.R.C. grant no. B/RG 82919 to one of us (M.C.T.). The localization of polypeptide hormones in the pharynx and gut of protochordates

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Thorndyke, M.C., Bevis, P.J.R. Endocrine cells in the gut of the ascidian Styela clava . Cell Tissue Res. 187, 159–165 (1978).

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Key words

  • Endocrine cells
  • Ascidian (Styela clava)
  • Gut epithelium
  • Electron microscopy