+1 Recommend
1 collections
      • Record: found
      • Abstract: found
      • Article: found

      Characterization of Estrogen Stimuli Sufficient to Initiate Cyclic Luteinizing Hormone Release in Acutely Ovariectomized Rats



      S. Karger AG

      Hypothalamus, Pituitary, LH secretion, Estradiol, Progesterone, Receptors

      Read this article at

          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.


          Estradiol (E)-filled Silastic capsules were implanted subcutaneously to characterize the estrogen stimulus sufficient to initiate cyclic LH secretion in female rats ovariectomized on diestrus 1 of the estrous cycle. Such capsules elevate preoptic area, hypothalamic and hypophysial cell nuclear estrogen receptor levels to proestrous values within ½ h following insertion; upon removal of the capsules, nuclear receptor levels decline monotonically to ovariectomized control levels by 8 h in brain and 12 h in pituitary. Three parameters of the E stimulus were studied:latent period, duration, and continuity. E stimuli, short in duration (7–12 h) and discontinuous in nature (3 h pulses 12 or 15 h apart), effectively stimulated LH surges on ‘proestrus’. However, these stimuli had to begin 30 h prior to the onset of LH release. Such a latent period for estrogen action was not observed when we monitored the ability of the same E stimuli to enhance pituitary responsiveness to GnRH. These studies demonstrate that the ‘rate-limiting step’ for estrogen’s positive feedback action is located within the estrogen-sensitive brain circuits controlling GnRH release and defines the temporal characteristics of E stimuli activating these circuits.

          Related collections

          Author and article information

          S. Karger AG
          26 March 2008
          : 34
          : 5
          : 315-322
          The Rockefeller University, New York, N.Y. (USA)
          123320 Neuroendocrinology 1982;34:315–322
          © 1982 S. Karger AG, Basel

          Copyright: 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. 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.

          Page count
          Pages: 8
          Original Paper


          Comment on this article