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

      Metabolism of GnRH in Man: Influence of Estrogens

      , , ,

      Hormone Research in Paediatrics

      S. Karger AG

      Tamoxifen, Metabolic clearance rate, GnRH

      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

          To clarify the influence of estrogens on the metabolism of gonadotropin-releasing hormone (GnRH), we studied the metabolic clearance rate (MCR) of GnRH (MCRgnrh), and the serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol and testosterone (total and free fraction) in 9 sexually mature men and 7 women under basal conditions and after treatment with the antiestrogen tamoxifen (2 × 10 mg/day p.o.) for 7 days. In women, the medication was started on day 7 ± 1 of their menstrual cycles. To calculate the MCR, synthetic GnRH was continuously infused (1.53 µg/min) and its serum levels were measured by a radioimmunoassay. During tamoxifen treatment we observed a small but significant decrease in the MCR in men (455 ± 48 to 357 ± 46 ml/min/1.86 m<sup>2</sup>), whereas the known cyclic increase in the MCR in women was blunted (1,769 ± 147 to 1,558 ± 119 ml/min/1.86 m<sup>2</sup>). There was a small but significant increase in LH levels in women (8.3 ± 2.1 to 11.5 ± 2.5 mU/ml). LH and testosterone levels in men, and FSH and estradiol levels in both sexes did not change significantly. Conclusion: (1) estrogens regulate the MCRg<sub>GnRH</sub> either directly or by changing gonadotropin levels, but the effect is only slight; (2) an enhanced metabolism of GnRH may contribute to the feedback of estrogens on the secretion of gonadotropins, and (3) the sex-specific difference of the MCR is presumably not caused by estrogens.

          Related collections

          Author and article information

          Journal
          HRE
          Horm Res Paediatr
          10.1159/issn.1663-2818
          Hormone Research in Paediatrics
          S. Karger AG
          1663-2818
          1663-2826
          1987
          1987
          28 November 2008
          : 25
          : 4
          : 199-205
          Affiliations
          Abteilung für klinische Endokrinologie, Medizinische Klinik, Universität Essen, BRD
          Article
          180653 Horm Res 1987;25:199–205
          10.1159/000180653
          3108133
          © 1987 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: 7
          Categories
          Original Paper

          Comments

          Comment on this article