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      Binding of Estradiol to Macromolecules in the Rat Neurohypophysis: Effects of Time of the Day, Pinealectomy and Melatonin Administration

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          Abstract

          The neurohypophysis of the spayed femalerat previously injected with a single dose of <sup>3</sup>H-estradiol took up and 75 min later retained significantly more radioactivity than the adenohypophysis. 86 to 92 % of the radioactivity in the neurohypophysis was chromato-graphically identified as estradiol. Cytosol fractions of rat neurohypophysis incubated with <sup>3</sup>H-estradiol and subjected to Sephadex G-25 chromatography exhibited significant amounts of radioactivity bound to high molecular weight components. Treatment with dextran-coated charcoal of nuclei-free neurohypophysial homogenates incubated with <sup>3</sup>H-estradiol of different specific activities uncovered a high affinity, low cupacity binding of estradiol to cytosol components. Testosterone and progesterone were about 60% as active as unlabeled estradiol in causing displacement of <sup>3</sup>H-estradiol from high affinity binding sites. Estradiol uptake by the rat neurohypophysis exhibited significant in vivo 24-h variations, being maximal during day-time. Pinealectomy or superior cervical ganglionectomy caused increases in the uptake of estradiol by the neurohypophysis, which were partially reversed by the administration of melatonin.

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          Author and article information

          Journal
          NEN
          Neuroendocrinology
          10.1159/issn.0028-3835
          Neuroendocrinology
          S. Karger AG
          0028-3835
          1423-0194
          1974
          1974
          20 March 2008
          : 14
          : 3-4
          : 174-186
          Affiliations
          Instituto Latinoamericano de Fisiología de la Reproducción (ILAFIR), Universidad del Salvador, San Miguel
          Article
          122257 Neuroendocrinology 1974;14:174–186
          10.1159/000122257
          4850756
          cab1c2de-5d9c-4a3c-877b-9cef3ee55b25
          © 1974 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
          : 31 May 1973
          : 27 September 1973
          Page count
          Pages: 13
          Categories
          Paper

          Endocrinology & Diabetes,Neurology,Nutrition & Dietetics,Sexual medicine,Internal medicine,Pharmacology & Pharmaceutical medicine
          Neurohypophysis,Melatonin,Estradiol,24-Hour rhythms,Sympathetic nervous system,Pineal

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