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

      The Effect of Systemic Administration of Dopamine and Apomorphine on Plasma LH and Prolactin Concentrations in Conscious Rats

      ,

      Neuroendocrinology

      S. Karger AG

      Dopamine, Apomorphine, LH, Prolactin

      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

          The effect of systemic administration of various doses of dopamine (DA) and apomorphine (APM) on plasma gonadotropin and prolactin (Prl) concentrations in ovariectomized (OVX) as well as in ovariectomized, estrogen-progesterone (OEP)-primed rats bearing indwelling jugular venous catheters was evaluated. Intravenous (i.v.) infusion or pulse injection of 0.9% NaCl had no significant effect on plasma titers of LH or Prl. I.v. infusion of DA at 4 µg/kg-b.w./min induced a progressive increase in circulating LH concentration in OEP rats while infusion at a similar dose in OVX animals had no effect on plasma LH. I.v. injection of 100 µg DA or APM significantly increased LH at 15 min in OVX rats. Similarly, in OEP rats 100 µg of DA elevated plasma LH at 30 and 90 min while APM induced a significant elevation of plasma LH at 15 min after injection. In OVX rats injection of DA i.p. at a dose of 5 mg/kg-b.w. did not alter plasma LH levels, but a dose of 50 mg/kg-b.w. produced a significant reduction in plasma LH concentration. APM injected i.p. at either 5 or 50 mg/kg-b.w. doses was nearly equally effective in lowering plasma LH and the suppressive effect was significantly greater than with similar doses of DA. A single injection of LH-RH (100 ng in 0.2 ml of 0.9% NaCl) in animals pretreated 15 min earlier with an effective dose of APM (5 mg/kg-b.w.) produced a peak increase in LH titers 15 min after injection. The increment in plasma LH following LH-RH in APM-treated rats was comparable to that in rats which had received saline instead of APM. Prl levels were significantly lowered by each dose of DA and APM in OVX as well as in OEP rats. There was no significant change in plasma FSH titers induced by either drug in any of the experiments. It is concluded that DA may have different actions depending upon the dose and the endocrine state of the animal. Thus, i.v. infusion of low doses of DA in OEP animals or by pulse injection in both OVX and OEP rats can elevate plasma LH by activating the release of LH-RH from the hypothalamus, while large doses of DA in OVX animals may suppress the release of LH-RH.

          Related collections

          Author and article information

          Journal
          NEN
          Neuroendocrinology
          10.1159/issn.0028-3835
          Neuroendocrinology
          S. Karger AG
          0028-3835
          1423-0194
          1978
          1978
          25 March 2008
          : 25
          : 4
          : 221-235
          Affiliations
          Department of Physiology, University of Texas Health Science Center at Dallas, Southwestern Medical School, Dallas, Tex.
          Article
          122744 Neuroendocrinology 1978;25:221–235
          10.1159/000122744
          349418
          © 1978 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: 15
          Categories
          Paper

          Comments

          Comment on this article