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

      Biphasic Effect of Orchiectomy on Pro-Opiomelanocortin Gene Expression in the Hypothalamus

      ,

      Neuroendocrinology

      S. Karger AG

      β-Endorphin, Orchiectomy, Hypothalamus, Pro-opiomelanocortin

      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

          Previous studies have shown that the hypothalamic concentration of pro-opiomelanocortin (POMC) mRNA and several POMC-derived peptides increases in the rat 4 weeks after orchiectomy and that this increase can be prevented by testosterone replacement. In this study, we have examined the short-term effects of orchiectomy on POMC gene expression in the medial basal hypothalamus (MBH). Adult male rats were studied at various time points between 1 day and 4 weeks after orchiectomy and compared to sham-orchiectomized rats. The MBH was homogenized and, after an aliquot was removed for β-endorphin (β-EP) radioimmunoassay, the RNA was isolated and the amount of POMC mRNA was measured using a solution hybridization SI nuclease protection assay. In the first experiment, POMC mRNA was significantly higher 4 weeks after orchiectomy compared to that of the intact controls: 1.34 ± 0.14vs.0.86 ± 0.04 pg/µg RNA (p < 0.01). Three days after orchiectomy, POMC mRNA was somewhat lower, 0.71 ± 0.06 pg/µg RNA, but not significantly different from the controls. In a second experiment, POMC mRNA levels were measured 1, 2, 3, 4 and 7 days after orchiectomy. At 1 and 2 days after orchiectomy, POMC mRNA was lower than the controls: 0.51 ± 0.02 and 0.52 ± 0.06 vs. 0.70 ± 0.09 pg/µg RNA. Levels then steadily increased to 0.61 ± 0.04, 0.70 ± 0.09 and 0.78 ± 0.11 pg/µg RNA at 3, 4 and 7 days after orchiectomy, respectively. The mean level at 1–2 days after orchiectomy was significantly less than the controls (p < 0.05). In a third experiment, POMC mRNA was again significantly lower 2 days after orchiectomy, 0.74 ± 0.05 pg/µg RNA, compared to 2 days after sham orchiectomy, 1.01 ± 0.12 pg/µg (p < 0.05). The decrease in POMC mRNA that we measured 2 days after orchiectomy, however, was not prevented by our regimen of testosterone replacement. The only significant change in β-EP content was the increase noted 4 weeks after orchiectomy which paralleled the increase in POMC mRNA. Thus, the effects of castration on POMC gene expression in the male rat appear to be biphasic with an initial decrease followed by a much later increase in POMC mRNA levels. The initial fall in POMC mRNA occurs at the time when luteinizing hormone (LH) levels are increasing and may thus play a role in modulating the early postcastration changes in gonadotropin-releasing hormone and LH secretion.

          Related collections

          Author and article information

          Journal
          NEN
          Neuroendocrinology
          10.1159/issn.0028-3835
          Neuroendocrinology
          S. Karger AG
          0028-3835
          1423-0194
          1990
          1990
          03 April 2008
          : 52
          : 5
          : 521-526
          Affiliations
          Department of Medicine, Columbia University College of Physicians and Surgeons, and Fishberg Research Center for Neurobiology, Mt. Sinai School of Medicine, New York, N.Y., USA
          Article
          125638 Neuroendocrinology 1990;52:521–526
          10.1159/000125638
          2126360
          © 1990 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: 6
          Categories
          Original Paper

          Comments

          Comment on this article