Age related changes in the time courses of response of plasma corticosterone and aldosterone to exogenously applied ACTH were simultaneously studied in old (female and male) Long-Evans rats and compared to both young and adult pentobarbitone-anesthetized and dexamethasone-pretreated control rats. Acute intravenous injection of either 0.5 or 50.0 ng ACTH (1-24)/100 g body weight increased plasma concentrations of the two steroids with a similar time course in all groups of rats. However, we observed a significant age-related attenuation in the plasma corticosteroid response. Thus, in old as compared to young rats there was a decrease of approximately 45, 40 and 30% in plasma corticosterone levels respectively 8 min after the lower dose of ACTH in female and 45 min after the higher dose in female and male rats. Similarly, an attenuated (approximately -38%) response of plasma aldosterone levels, induced 45 min after the higher dose of ACTH, was observed both in old female and male rats. These results suggest that the previously reported age-related decreases of in vivo corticosterone and aldosterone secretion are, at least in part, due to a reduced capacity of adrenocortical cells for steroid biosynthesis and release in response to stimulation by ACTH.

This content is only available via PDF.
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.