The potential involvement of the sympathoadrenal system in stress-induced secretion of peptides from the intermediate lobe of the pituitary gland and the activation of the pituitary-adrenal axis was studied. Male Wistar rats were subjected to control procedures, to sympathectomy by chronic administration (8 weeks) of guanethidine and/or to medullectomy by adrenal enucleation 9 weeks prior to exposure to forced immobilization stress for various periods of time. In intact or sham-operated rats, immobilization caused a prompt increase of circulating norepinephrine, epinephrine (EPI), corticosterone and of immunoreactive adrenocorticotropic hormone (ACTHi), α-melanocyte-stimulating hormone (α-MSHi) and β-endorphin (β-ENDi). Peak levels of pituitary hormones were found after 10 min of stress exposure, but fell to less than 30% of these levels after 2.5 h of immobilization. Adrenal medullectomy, which abolished the stress-induced release of EPI, reduced the acute increase of plasma α-MSHi and β-ENDi, but dit not influence the acute increase of plasma ACTHi during immobilization stress. Also in medullectomized plus sympathectomized rats, the initial stress response of circulating ACTHi was not different from that of controls. Adrenal medullectomy with or without additional sympathectomy caused a marked increase in plasma ACTHi concentrations after prolonged stress exposure. We conclude that: (1) catecholamines originating from the adrenalmedulla facilitate the stress-induced secretion of intermediate lobe peptides (α-MSHi, β-ENDi); (2) catecholamines from the sympathoadrenomedullary system do not contribute to the acute release of ACTH during immobilization stress; (3) the sympathoadrenomedullary system is involved in the secondary reduction of circulating ACTHi levels seen during prolonged stress.

Keywords:
Sympathoadrenal activity, Adrenocorticotropic hormone, α-Melanocyte-stimulating hormone, β-Endorphin, Epinephrine, Norepinephrine, Sympathectomy, Adrenalenucleation, Immobilization stress, Stress response
This content is only available via PDF.
© 1987 S. Karger AG, Basel
1987
Copyright / Drug Dosage / Disclaimer
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.
You do not currently have access to this content.