Effects of chronic ethanol administration and withdrawal on incorporation of arachidonate into membrane phospholipids.
A plasma membrane fraction isolated from cerebral cortex of control and ethanol-treated rats was used to study the effects of chronic ethanol administration on uptake of arachidonate by membrane phospholipids. Upon incubation of the membranes with [(14)C] arachidonic acid in the presence of ATP, Mg(2+), and CoA, radioactivity was incorporated into all of the phospholipids, although a large proportion of the label was found in phosphatidylinositols (PI, 60%) and phosphatidylcholines (PC, 20%). Rats given ethanol (8-10 g/kg body wt) via intubation in the form of a liquid diet for 4 weeks showed an increase (17-20%) in arachidonate incorporation into PI and PC as compared to phosphatidylethanolamines (PE) and phosphatidylserines (PS). A similar increase in uptake activity was observed at 2 or 24 h upon withdrawal of ethanol, but uptake activity returned readily to that of control level by 72 h. The method described in this study is a sensitive and reliable procedure for monitoring the arachidonoyl turnover activity in neural membranes with respect to chronic ethanol induction and withdrawal.
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Sinclair Comparative Medicine Research Farm and Biochemistry Department, University of Missouri, Columbia, MO 65203, U.S.A.
Kelleher
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Sun
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