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

      Strain Differences for Preoptic Stimulation of Ovulation in Cyclic, Spontaneously Persistent-Estrous, and Androgen-Sterilized Rats

      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.


          The CD (Charles River) strain of rats differs in several important respects from our inbred Osborne Mendel (O-M) strain. The critical period for the ovulatory surge of gonadotropin in proestrus is less sharply limited in CD rats. They are much more refractory to preoptic (POA) electrochemical stimulation for ovulation, not only in normally cycling females, but strikingly so in androgen-sterilized (TP) females, as well as in rats having spontaneous persistent estrus (PE). In proestrous 4-day cyclic CD females ‘blocked’ with pentobarbital, a much larger stimulus (100 µA × 30 sec = 3000 µcoulombs) was required to fully ovulate all subjects than was needed in similar O-M rats (10 µA × 20 sec = 200 µcoulombs). While 5/6 O-M PE rats ovulated in response to massive unilateral POA stimulation (3000 µcoulombs), all of 6 CD PE rats failed to ovulate. Even bilateral POA stimulation with these parameters induced ovulation in only 3/10 rats. O-M TP rats had low POA thresholds close to those of cyclic O-M females, while only 1/6 CD TP rats gave even a partial response (5 tubal ova) to massive bilateral stimulation. CD TP rats also differed from O-M TP rats by secreting abundant prolactin in spite of the constant estrus. This was shown by prominent milk cysts in the mammary glands at 8–9 months of age and by spontaneous pseudopregnancy after corpora lutea were induced by LH injection. O-M TP rats had no mammary development and experienced only a short diestrus after LH injection. Whether there is a common basis for these strain differences remains uncertain.

          Related collections

          Author and article information

          S. Karger AG
          19 March 2008
          : 6
          : 2
          : 98-108
          Department of Anatomy, Duke University School of Medicine, Durham, North Carolina, USA
          121912 Neuroendocrinology 1970;6:98–108
          © 1970 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: 11


          Comment on this article