16
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found

      A Mechanism Additional to Cyclic AMP Accumulation for Vasoactive Intestinal Peptide-Induced Prolactin Release

      research-article

      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

          Vasoactive intestinal peptide (VIP) is a prolactin (PRL)-releasing factor which has been proposed to exert its secreting property by activating the adenylate cyclase enzyme. The present study shows that the omission of external Ca<sup>2+</sup> did not affect the ability of VIP to induce PRL release while it completely abolished the VIP stimulatory effect on adenylate cyclase. We found that VIP (500 nM) stimulated PRL secretion in a time-dependent manner reaching a plateau at 3 min. This pattern was not changed when Ca<sup>2+</sup> was omitted from the incubation medium. When tested at different concentrations, VIP stimulated PRL release with EC<sub>50</sub> values of 1.3 n M in the presence of Ca<sup>2+</sup> and 30 n M in the absence of Ca<sup>2+</sup>. On the other hand, Ca<sup>2+</sup> removal completely suppressed the VIP-induced cAMP formation. VIP (200 n M) was also found to activate Ca<sup>2+</sup> influx into pituitary cells. The increase in Ca<sup>2+</sup> permeability showed a peak at 5 s and remained significantly higher than control values until 1 min. In conclusion, in an experimental condition where Ca<sup>2+</sup> was omitted from the medium, VIP was found to induce PRL release without stimulating cAMP production. This cAMP-independent PRL release was blocked by preincubation of the cells with 1 µg/ml pertussis toxin. An additional mechanism other than adenylate cyclase activation or Ca<sup>2+</sup> entry is proposed to sustain VIP-induced PRL release.

          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
          : 51
          : 4
          : 481-486
          Affiliations
          Institute of Pharmacology and Experimental Therapeutics, School of Medicine, Brescia University, Italy
          Article
          125378 Neuroendocrinology 1990;51:481–486
          10.1159/000125378
          2161088
          4a426148-074e-40ef-bf8c-a5af2caaedfe
          © 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.

          History
          : 10 February 1989
          : 06 September 1989
          Page count
          Pages: 6
          Categories
          Original Paper

          Endocrinology & Diabetes,Neurology,Nutrition & Dietetics,Sexual medicine,Internal medicine,Pharmacology & Pharmaceutical medicine
          Vasoactive intestinal peptide,Cyclic AMP,Prolactin,Pituitary,Calcium

          Comments

          Comment on this article