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      Testosterone and Dihydrotestosterone, but Not Estradiol, Selectively Maintain Pituitary and Serum Follicle-Stimulating Hormone in Gonadotropin-Releasing Hormone Antagonist Treated Male Rats

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          Abstract

          Recently it has been found that testosterone can maintain and restimulate serum and pituitary follicle-stimulating hormone (FSH) in the gonadotropin-releasing hormone (GnRH) antagonist treated adult male rat. The present investigation was undertaken to determine (1) which metabolite of testosterone, dihydrotestosterone (DHT), or estradiol accounts for the effects of testosterone in GnRH antagonist suppressed rats and (2) whether these effects of testosterone are influenced by other testicular factors. Eight groups of 6–8 adult male Sprague-Dawley rats were subjected to the following treatments: vehicle, GnRH antagonist (75 µg/day s.c), testosterone-filled Silastic implants (3 × 5 cm, s.c), DHT-filled Silastic implants (3 × 5 cm, s.c), estradiol ben-zoate (15 µg/day s.c), and combined administration of GnRH antagonist with either steroid. In addition, the GnRH antagonist/ testosterone treatment regimen was applied to rats orchidectomized 72 h prior to initiation of treatments. After 3 weeks of treatment, serum was analyzed for concentrations of luteinizing-hormone (LH), FSH, testosterone, DHT, and estradiol. Pituitary extracts were analyzed for LH and FSH content. Except for the vehicle-treated groups, serum and pituitary LH concentrations were markedly suppressed by all treatments. In intact rats treated with GnRH antagonist alone and/or estradiol, the pituitary FSH level was reduced by more than 70% relative to controls, while both testosterone and DHT maintained pituitary FSH. Similarly, testosterone and DHT, but not estradiol, delayed the decline of serum FSH induced with GnRH antagonist alone. In orchidectomized animals, testosterone was also capable of preventing a reduction of pituitary FSH despite concomitant GnRH antagonist administration. It is concluded that testosterone and DHT selectively maintain FSH in the GnRH antagonist treated male rat. This paradoxical stimulation of FSH occurs in the absence of other testicular factors.

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          Author and article information

          Journal
          NEN
          Neuroendocrinology
          10.1159/issn.0028-3835
          Neuroendocrinology
          S. Karger AG
          0028-3835
          1423-0194
          1989
          1989
          02 April 2008
          : 49
          : 4
          : 395-401
          Affiliations
          Max Planck Clinical Research Unit for Reproductive Medicine and Department of Reproductive Medicine, University of Münster, FRG
          Article
          125144 Neuroendocrinology 1989;49:395–401
          10.1159/000125144
          2497399
          cf150130-2079-4e76-99c6-78c05e6a02cd
          © 1989 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.

          History
          : 07 March 1988
          : 11 August 1988
          Page count
          Pages: 7
          Categories
          Original Paper

          Endocrinology & Diabetes,Neurology,Nutrition & Dietetics,Sexual medicine,Internal medicine,Pharmacology & Pharmaceutical medicine
          Testis,Dihydrotestosterone,Estradiol,Testosterone,Follicle-stimulating hormone,Luteinizing hormone,Gonadotropin-releasing hormone antagonist

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