0
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found

      Preferential Distribution of C-Terminal Fragments of [Hydroxyproline 9]LHRH in the Rat Hippocampus and Olfactory Bulb

      Read this article at

      ScienceOpenPublisherPubMed
      Bookmark
          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.

          Abstract

          Several molecular forms related to the decapeptide LHRH were characterized and quantified in various brain structures of intact and castrated male and female rats. Distinct moieties were separated by high performance liquid chro-matography (HPLC) and radioimmunoassayed against anti-LHRH antibodies of different specificities. The hypothalamus contained the highest concentration of LHRH-like material detected by the antisera. The predominant (89%) molecular form recovered from that structure was LHRH itself; 9% of the material corresponded to [hydroxyproline<sup>9</sup>]LHRH ([Hyp<sup>9</sup>]LHRH), an endogenous posttranslational product of the LHRH precursor, and the residual immunoreactivity was accounted for by C-terminal fragments of both decapeptides, as assessed after labelling HPLC columns with appropriate synthetic or endogenous hypothalamic peptides. The proportions were the same in both sexes and were not affected by castration, in spite of a lesser overall LHRH activity in females and in castrates. LHRH and [Hyp<sup>9</sup>]LHRH were also detected in the olfactory bulb and the hippocampus. In these structures however, most (97%) LHRH-related molecules corresponded to C-fragments derived from [Hyp<sup>9</sup>]LHRH, whereas only very few fragments derived from the nonhydroxylated decapeptide were found. Sex or castration affected neither total nor relative concentrations of LHRH-derived molecules in the olfactory bulb and the hippocampus. Taken altogether, these observations are suggestive of a different LHRH metabolic regulation in neurons projecting to either the median eminence or extrahypothalamic areas. In the latter case, larger amounts of the LHRH precursor appear processed to [Hyp<sup>9</sup>]LHRH. Recovery of relatively high concentrations of [Hyp<sup>9</sup>] LHRH C-fragments in the olfactory bulb and the hippocampus reflects the higher resistance of the Hyp<sup>9</sup>-Gly<sup>10</sup>-NH<sub>2</sub> than the Pro<sup>9</sup>-Gly<sup>10</sup>-NH<sub>2</sub> peptidic bond to hydrolysis by the postproline cleaving enzyme. In view of reports that intracerebral administration of C-terminal fragments of LHRH are able to trigger sex behavior, our finding that extrahypothalamic structures contain relatively high concentrations of the [Hyp<sup>9</sup>]LHRH-derived, more stable C-fragments suggests that these catabolites may have a role in the regulation of sex behavior.

          Related collections

          Author and article information

          Journal
          NEN
          Neuroendocrinology
          10.1159/issn.0028-3835
          Neuroendocrinology
          S. Karger AG
          0028-3835
          1423-0194
          1993
          1993
          08 April 2008
          : 58
          : 2
          : 240-250
          Affiliations
          Unité INSERM 159 de Dynamique des Systèmes Neuroendocriniens, Centre Paul Broca, Paris, France
          Article
          126539 Neuroendocrinology 1993;58:240–250
          10.1159/000126539
          8264870
          © 1993 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
          Categories
          Original Paper

          Comments

          Comment on this article