ARACHIDONIC-ACID AND RELATED METHYL-ESTER MEDIATE PROTEIN KINASE-C ACTIVATION IN INTACT PLATELETS THROUGH THE ARACHIDONATE METABOLISM PATHWAYS
ARACHIDONIC-ACID AND RELATED METHYL-ESTER MEDIATE PROTEIN KINASE-C ACTIVATION IN INTACT PLATELETS THROUGH THE ARACHIDONATE METABOLISM PATHWAYS
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DOI：
10.1016/0006-291x(90)91983-y
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发表时间：
1990-06-29
影响因子：
3.1
通讯作者：
CASTAGNA, M
中科院分区：
文献类型：
--
作者：
FAN, XT;HUANG, XP;CASTAGNA, M
Unlike unsaturated fatty acids, which almost fully activated purified brain protein kinase C in a phosphatidylserine- and Ca2+-free reaction, related methyl esters were poorly active in vitro. In contrast, methyl arachidonate was revealed to be as potent as arachidonic acid in activating protein kinase C in intact platelets. Arachidonic acid-mediated activation peaked at 20 s while methyl arachidonate-mediated activation plateaued at 2 min when both lipids were added at 50 .mu.M. At concentrations higher than 0.3 mM, all tested unsaturated fatty acids and related methyl esters were weak activators of the enzyme, with the exception of linolenic acid and methyl linolenate which evoked strong enzyme activation. However, inhibitors of arachidonate metabolism blocked both arachidonic-acid and methyl-arachidonate-induced responses. At 5 .mu.M arachidonic acid and methyl arachidonate, protein kinase C activation was due to a cyclooxygenase product(s) whereas at 50 .mu.M the lipoxygenase pathway was mostly involved in the reaction. Therefore, arachidonic acid and its methyl ester activate protein kinase C in platelets mainly through action of their metabolites and eicosanoid synthesis. It is suggested that such indirect protein kinase C activation may account for the tumor-promoting activity of unsaturated fatty acids and related methyl esters.
