Background: Asymmetric dimethylarginine (ADMA), the inhibitor of nitric oxide synthase (NOS), has been reported to be associated with glucose metabolism, but its mechanisms remain unknown. Methods: In 3T3-L1 adipocytes, we measured the effects of ADMA on glucose transport process under basal or insulin-induced condition, and examined the production of nitric oxide (NO), reactive oxygen species (ROS) and tumor necrosis factor alpha (TNF-α), and the expression of toll-like receptor 4 (TLR4). Results: ADMA significantly impaired basal or insulin-stimulated 2-deoxy- [3H] glucose uptake, and decreased the expression of insulin receptor substrate-1 (IRS-1) and glucose transporter-4 (GLUT4). Phosphorylated protein of IRS-1 and translocation of GLUT4 with insulin-stimulation were also inhibited by ADMA. NO decreased, while production of ROS and TNF-α, and expression of TLR4 increased after ADMA treatment. Vitamin E reduced the effects of ADMA on glucose transport system, and on NO, ROS and TLR4. Moreover, vitamin E decreased ADMA contents by up-regulating dimethylarginine dimethylaminohydrolase (DDAH) activity in adipocytes. Though L-arginine also increased NO level, but failed to reduce the effects of ADMA. Conclusion: ADMA significantly impairs both basal and insulin-stimulated glucose transport in adipocytes, which may relate to activation of the ROS/TLR4 pathway.

Keywords:
Asymmetric dimethylarginine, Glucose, Adipocytes, Oxidative stress, Toll-like receptor 4
This content is only available via PDF.
© 2009 S. Karger AG, Basel
2009
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.