Experimental Evidence for the Early Commitment of the Presumptive AdenohypophysisElAmraoui A. · Dubois P.M.
CNRS URA 1454, Université Claude Bernard, Neuroendocrinologie, Faculté de Médecine Lyon-Sud, Oullins, France
Do you have an account?
- Rent for 48h to view
- Buy Cloud Access for unlimited viewing via different devices
- Synchronizing in the ReadCube Cloud
- Printing and saving restrictions apply
Rental: USD 8.50
Cloud: USD 20.00
Article / Publication Details
To investigate the commitment potentialities of the adenohypophyseal tissue, its presumptive territory, localized in the anterior ridge of the neural plate in the chick embryo, was surgically removed from 2- to 4-somite stages of development. At later stages, operated embryos were progressively collected to study the extent (if any) of the adenohypophyseal tissue. The results revealed that Rathke’s pouch and later the adenohypophysis were completely absent in 33 out of the 45 studied embryos. The surrounding tissues in the operated embryos developped in a comparable manner to those in normal embryos. The head morphogenesis was not affected by the surgical ablation. Strikingly, no regeneration of adenohypophyseal tissue was observed in the operated embryos. At younger stages, a very small invagination was observed close to the diencephalon of 9 out of the 45 studied embryos. Its extent was reduced to less than 20% when compared to normal embryos at the same stages. This epithelial invagination is believed therefore to be a residuum of the stomodeal ectoderm and/or the stomodeo-adenohypophyseal channel which normally regresses at later stages of development. Therefore, the anterior ridge of the neural plate seems irrevocably destined to form adenohypophyseal tissue even as early as 2- to 4-somite stages. This suggests that the adenohypophysis presumptive territory is already committed prior to neural tube closure and also seems to confirm its origin from the neural primordium in avian embryos. Since close topological relationships link the presumptive adenohypophysis territory with both those of the hypothalamus and ectoderm of nasal cavity, possible developmental influences through such intimate contacts cannot be totally excluded.
© 1993 S. Karger AG, Basel
Article / Publication Details
Copyright / Drug Dosage / DisclaimerCopyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.