The effect of Cd^2+, Pb^2+ and Hg^2+ on the Ca^2+-ATPase activity of sarcoplasmic reticulum from rabbit muscle was studied. The concentration of relevant free and complex species for the assay conditions have been computed. As a result, ATP hydrolysis was found to be inhibited with an IC(50) value of 950 nmol/l free Cd^2+ or 95 nmol/l free Pb^2+. Although calculation of the free Hg2+ was not possible, the comparison of the IC50 values for total metal ions show that Hg^2+ is the strongest inhibitor of enzyme activity. The inhibition by Cd^2+ seems to be independent of substrate concentration, whereas the inhibitory effect of Pb^2+ is lowered in the presence of higher MgATP concentrations. Our data illustrate that the three heavy metals are potent inhibitors of the Ca^2+ pump. Therefore low concentrations of these metal ions may disturb intracellular Ca^2+ homeostasis and act on Ca^2+-mediated cell functions.

Keywords:
Ca^2+-ATPase, Sarcoplasmic reticulum, Cadmium, Lead, Mercury
This content is only available via PDF.
1991
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.