The effect of choline deficiency on the outer membranes of rat liver mitochondria.

The outer membranes of mitochondria prepared from the liver of rats kept 12 days on a choline-deficient diet were analyzed for changes in phospholipid and protein content. The total amount of phospholipid in the outer membranes was not affected by the deficiency. There was, however, a significant decrease in the amount of phosphatidylcholine and an increase in phosphatidylethanolamine. The alterations in the membrane phospholipids were reflected in a reduction in the fluorescence of the membrane probe, 8-anilino-1-naphthalene sulfonate. Choline deficiency also affected the protein composition of the outer membranes as judged by electrophoretic analysis; however, the activity of several enzymes which serve as markers for the outer membrane was not affected by the deficiency.