Subcellular fractions (brush border, mitochondria, microsomes and plasma membranes)are isolated from the rat intestinal epithelial cells. A comparison was made between the effect of cold storage, freeze-thawing, heating and of some chemicals (DMSO, DTT, glycerol,sucrose) on the stability of Mg^2+ and (Na^+-K^+)-dependent ATPases in these fractions in order to determine possible differences linked to the localization in the enterocyte. Enzymatic activities were found more stable at — 20 °C than at +4 °C. Microsomal (Na^+-K^+)-ATPase increased in activity until the 8th day, then declined. Brush border (Na^+-K^+)-ATPase was the least resistant of all fractions. For Mg^2+-ATPase, that from mitochondria was that had lost much more activity (84 %) in 15 days at + 4 °C. With freeze-thawing there was a comparable decrease in all activities (20—35 %). By heating between 35 and 60 °C, Mg^2+-ATPase was shown to be more heat resistant than (Na^+-K^+)-ATPase. The addition of some stabilizing chemicals (DMSO, glycerol, sucrose) improved the heat stability of the two enzymes: better results were obtained with glycerol for Mg^2+-ATPase and sucrose for(Na^+-K^+)-ATPase. These differences might be due to the composition in membrane lipids or to the nature of the enzymes studied.

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.