Changes in fatty acid composition of phospholipids from liver microsomes and nuclei in rats fed a choline-free diet.

Male F-344 rats were fed a choline-free (CF) diet, and changes in phospholipid content, phospholipid fatty acids and phospholipase A2 activity in liver nuclei and microsomes were examined during the first 72 hr. Both nuclei and microsomes showed a decrease in phosphatidylcholine (PC) content. Microsomes showed an increase in PC arachidonate while nuclei showed a decrease. Also, microsomes showed increased activity of phospholipase A2 (PLA2) while nuclei did not. These observations are consistent with the hypothesis that the absence of diene conjugates in liver microsomes in the rats on the CF diet may reflect the increased rate of removal of peroxidized fatty acids by phospholipase A2.