계명대학교 의학도서관 Repository

d-α-Tocopherol prevents the hyperglycemia induced activation of diacylglycerol (DAG)-protein kinase C (PKC) pathway in vascular smooth muscle cell by an increase of DAG kinase activity

Metadata Downloads
Author(s)
In-Kyu LeeDaisuke KoyaHidehiro IshiHideo KanohGeorge L. King
Keimyung Author(s)
Lee, In Kyu
Department
Dept. of Internal Medicine (내과학)
Journal Title
Diabetes Research and Clinical Practice
Issued Date
1999
Volume
45
Issue
2-3
Abstract
We have reported that d-a-tocopherol can prevent hyperglycemia-induced activation of DAG and PKC levels in
vascular tissues as well as normalizing retinal blood flow and renal hyperfiltration. The mechanism of this effect,
however, is not clear. Aside from a-tocopherol’s principal role as an antioxidant agent, it has also been shown to act
as a membrane stabilizer. Another possibility is that the effect of a-tocopherol is focused on the activation of DAG
kinase, which is a key enzyme in the metabolism of DAG. Therefore, in this study, we examined the effect of
a-tocopherol on the DAG kinase activity in vascular smooth muscle cell. We have also examined the effect of
a-tocopherol, its analogues, and probucol on DAG kinase activities and expression. The present study showed that
d-a-tocopherol’s inhibitory effect on DAG-PKC pathway is by increasing DAG kinase activity in rat and human
vascular smooth muscle cell (VSMC). Total DAG level was increased by 40910% (mean9S.E.) (PB0.05) in human
VSMC, after exposure to 22 vs 5 mM glucose. This increase was normalized by d-a-tocopherol treatment in a
concentration-dependent manner. In parallel, DAG kinase activation by d-a-tocopherol was also induced in a timeand
dose-dependent manner. DAG kinase activity was increased by 57919% (PB0.05) in human VSMC and
112935% (PB0.05) in rat VSMC after 24 h of incubation with d-a-tocopherol (100 mg:ml). Another lipophilic
antioxidant, probucol, also increased DAG kinase activity by 124934%, but other vitamin E analogues with much
less antioxidant potencies were ineffective. Western blots of various DAG kinase isoforms were not changed by
d-a-tocopherol treatment. These results provide strong and detailed evidence that d-a-tocopherol can prevent
hyperglycemia induced DAG-PKC activation by enhancing DAG kinase activity, probably through an antioxidant
effect. © 1999 Elsevier Science Ireland Ltd. All rights reserved.
Keimyung Author(s)(Kor)
이인규
Publisher
School of Medicine
Citation
In-Kyu Lee et al. (1999). d-α-Tocopherol prevents the hyperglycemia induced
activation of diacylglycerol (DAG)-protein kinase C (PKC)
pathway in vascular smooth muscle cell by an increase of
DAG kinase activity. Diabetes Research and Clinical Practice, 45(2–3), 183–190. doi: 10.1016/S0168-8227(99)00048-0
Type
Article
ISSN
0168-8227
Source
http://lps3.www.sciencedirect.com.proxy.dsmc.or.kr/science/article/pii/S0168822799000480?via%3Dihub
DOI
10.1016/S0168-8227(99)00048-0
URI
https://kumel.medlib.dsmc.or.kr/handle/2015.oak/35579
Appears in Collections:
1. School of Medicine (의과대학) > Dept. of Internal Medicine (내과학)
Authorize & License
  • Authorize공개
  • EmbargoForever
Files in This Item:

Items in Repository are protected by copyright, with all rights reserved, unless otherwise indicated.